Kubectl Plugin

CloudNativePG provides a plugin for kubectl to manage a cluster in Kubernetes.

Install

You can install the cnpg plugin using a variety of methods.

Note

For air-gapped systems, installation via package managers, using previously downloaded files, may be a good option.

Via the installation script

curl -sSfL \
  https://github.com/cloudnative-pg/cloudnative-pg/raw/main/hack/install-cnpg-plugin.sh | \
  sudo sh -s -- -b /usr/local/bin

Using the Debian or RedHat packages

In the releases section of the GitHub repository, you can navigate to any release of interest (pick the same or newer release than your CloudNativePG operator), and in it you will find an Assets section. In that section are pre-built packages for a variety of systems. As a result, you can follow standard practices and instructions to install them in your systems.

Debian packages

For example, let's install the 1.25.0-rc1 release of the plugin, for an Intel based 64 bit server. First, we download the right .deb file.

wget https://github.com/cloudnative-pg/cloudnative-pg/releases/download/v1.25.0-rc1/kubectl-cnpg_1.25.0-rc1_linux_x86_64.deb \
  --output-document kube-plugin.deb

Then, with superuser privileges, install from the local file using dpkg:

$ sudo dpkg -i kube-plugin.deb
Selecting previously unselected package cnpg.
(Reading database ... 6688 files and directories currently installed.)
Preparing to unpack kube-plugin.deb ...
Unpacking cnpg (1.25.0-rc1) ...
Setting up cnpg (1.25.0-rc1) ...

RPM packages

As in the example for .rpm packages, let's install the 1.25.0-rc1 release for an Intel 64 bit machine. Note the --output flag to provide a file name.

curl -L https://github.com/cloudnative-pg/cloudnative-pg/releases/download/v1.25.0-rc1/kubectl-cnpg_1.25.0-rc1_linux_x86_64.rpm \
  --output kube-plugin.rpm

Then, with superuser privileges, install with yum, and you're ready to use:

$ sudo yum --disablerepo=* localinstall kube-plugin.rpm
Failed to set locale, defaulting to C.UTF-8
Dependencies resolved.
====================================================================================================
 Package            Architecture         Version                   Repository                  Size
====================================================================================================
Installing:
 cnpg               x86_64               1.25.0-rc1-1                  @commandline                20 M

Transaction Summary
====================================================================================================
Install  1 Package

Total size: 20 M
Installed size: 78 M
Is this ok [y/N]: y

Using Krew

If you already have Krew installed, you can simply run:

kubectl krew install cnpg

When a new version of the plugin is released, you can update the existing installation with:

kubectl krew update
kubectl krew upgrade cnpg

Using Homebrew

Note

Please note that the Homebrew community manages the availability of the kubectl-cnpg plugin on Homebrew.

If you already have Homebrew installed, you can simply run:

brew install kubectl-cnpg

When a new version of the plugin is released, you can update the existing installation with:

brew update
brew upgrade kubectl-cnpg

Note

Auto-completion for the kubectl plugin is already managed by Homebrew. There's no need to create the kubectl_complete-cnpg script mentioned below.

Supported Architectures

CloudNativePG Plugin is currently built for the following operating system and architectures:

  • Linux
    • amd64
    • arm 5/6/7
    • arm64
    • s390x
    • ppc64le
  • macOS
    • amd64
    • arm64
  • Windows
    • 386
    • amd64
    • arm 5/6/7
    • arm64

Configuring auto-completion

To configure auto-completion for the plugin, a helper shell script needs to be installed into your current PATH. Assuming the latter contains /usr/local/bin, this can be done with the following commands:

cat > kubectl_complete-cnpg <<EOF
#!/usr/bin/env sh

# Call the __complete command passing it all arguments
kubectl cnpg __complete "\$@"
EOF

chmod +x kubectl_complete-cnpg

# Important: the following command may require superuser permission
sudo mv kubectl_complete-cnpg /usr/local/bin

Important

The name of the script needs to be exactly the one provided since it's used by the kubectl auto-complete process

Use

Once the plugin is installed and deployed, you can start using it like this:

kubectl cnpg COMMAND [ARGS...]

Note

The plugin automatically detects if the standard output channel is connected to a terminal. In such cases, it may add ANSI colors to the command output. To disable colors, use the --color=never option with the command.

Generation of installation manifests

The cnpg plugin can be used to generate the YAML manifest for the installation of the operator. This option would typically be used if you want to override some default configurations such as number of replicas, installation namespace, namespaces to watch, and so on.

For details and available options, run:

kubectl cnpg install generate --help

The main options are:

  • -n: specifies the namespace in which to install the operator (default: cnpg-system).
  • --control-plane: if set to true, the operator deployment will include a toleration and affinity for node-role.kubernetes.io/control-plane.
  • --replicas: sets the number of replicas in the deployment.
  • --watch-namespace: specifies a comma-separated list of namespaces to watch (default: all namespaces).
  • --version: defines the minor version of the operator to be installed, such as 1.23. If a minor version is specified, the plugin installs the latest patch version of that minor version. If no version is supplied, the plugin installs the latest MAJOR.MINOR.PATCH version of the operator.

An example of the generate command, which will generate a YAML manifest that will install the operator, is as follows:

kubectl cnpg install generate \
  -n king \
  --version 1.23 \
  --replicas 3 \
  --watch-namespace "albert, bb, freddie" \
  > operator.yaml

The flags in the above command have the following meaning: - -n king install the CNPG operator into the king namespace - --version 1.23 install the latest patch version for minor version 1.23 - --replicas 3 install the operator with 3 replicas - --watch-namespace "albert, bb, freddie" have the operator watch for changes in the albert, bb and freddie namespaces only

Status

The status command provides an overview of the current status of your cluster, including:

  • general information: name of the cluster, PostgreSQL's system ID, number of instances, current timeline and position in the WAL
  • backup: point of recoverability, and WAL archiving status as returned by the pg_stat_archiver view from the primary - or designated primary in the case of a replica cluster
  • streaming replication: information taken directly from the pg_stat_replication view on the primary instance
  • instances: information about each Postgres instance, taken directly by each instance manager; in the case of a standby, the Current LSN field corresponds to the latest write-ahead log location that has been replayed during recovery (replay LSN).

Important

The status information above is taken at different times and at different locations, resulting in slightly inconsistent returned values. For example, the Current Write LSN location in the main header, might be different from the Current LSN field in the instances status as it is taken at two different time intervals.

kubectl cnpg status sandbox

Cluster Summary
Name:                default/sandbox
System ID:           7423474350493388827
PostgreSQL Image:    ghcr.io/cloudnative-pg/postgresql:16.4
Primary instance:    sandbox-1
Primary start time:  2024-10-08 18:31:57 +0000 UTC (uptime 1m14s)
Status:              Cluster in healthy state
Instances:           3
Ready instances:     3
Size:                126M
Current Write LSN:   0/604DE38 (Timeline: 1 - WAL File: 000000010000000000000006)

Continuous Backup status
Not configured

Streaming Replication status
Replication Slots Enabled
Name       Sent LSN   Write LSN  Flush LSN  Replay LSN  Write Lag  Flush Lag  Replay Lag  State      Sync State  Sync Priority  Replication Slot
----       --------   ---------  ---------  ----------  ---------  ---------  ----------  -----      ----------  -------------  ----------------
sandbox-2  0/604DE38  0/604DE38  0/604DE38  0/604DE38   00:00:00   00:00:00   00:00:00    streaming  async       0              active
sandbox-3  0/604DE38  0/604DE38  0/604DE38  0/604DE38   00:00:00   00:00:00   00:00:00    streaming  async       0              active

Instances status
Name       Current LSN  Replication role  Status  QoS         Manager Version  Node
----       -----------  ----------------  ------  ---         ---------------  ----
sandbox-1  0/604DE38    Primary           OK      BestEffort  1.25.0-rc1           k8s-eu-worker
sandbox-2  0/604DE38    Standby (async)   OK      BestEffort  1.25.0-rc1           k8s-eu-worker2
sandbox-3  0/604DE38    Standby (async)   OK      BestEffort  1.25.0-rc1           k8s-eu-worker

If you require more detailed status information, use the --verbose option (or -v for short). The level of detail increases each time the flag is repeated:

kubectl cnpg status sandbox --verbose

Cluster Summary
Name:                default/sandbox
System ID:           7423474350493388827
PostgreSQL Image:    ghcr.io/cloudnative-pg/postgresql:16.4
Primary instance:    sandbox-1
Primary start time:  2024-10-08 18:31:57 +0000 UTC (uptime 2m4s)
Status:              Cluster in healthy state
Instances:           3
Ready instances:     3
Size:                126M
Current Write LSN:   0/6053720 (Timeline: 1 - WAL File: 000000010000000000000006)

Continuous Backup status
Not configured

Physical backups
No running physical backups found

Streaming Replication status
Replication Slots Enabled
Name       Sent LSN   Write LSN  Flush LSN  Replay LSN  Write Lag  Flush Lag  Replay Lag  State      Sync State  Sync Priority  Replication Slot  Slot Restart LSN  Slot WAL Status  Slot Safe WAL Size
----       --------   ---------  ---------  ----------  ---------  ---------  ----------  -----      ----------  -------------  ----------------  ----------------  ---------------  ------------------
sandbox-2  0/6053720  0/6053720  0/6053720  0/6053720   00:00:00   00:00:00   00:00:00    streaming  async       0              active            0/6053720         reserved         NULL
sandbox-3  0/6053720  0/6053720  0/6053720  0/6053720   00:00:00   00:00:00   00:00:00    streaming  async       0              active            0/6053720         reserved         NULL

Unmanaged Replication Slot Status
No unmanaged replication slots found

Managed roles status
No roles managed

Tablespaces status
No managed tablespaces

Pod Disruption Budgets status
Name             Role     Expected Pods  Current Healthy  Minimum Desired Healthy  Disruptions Allowed
----             ----     -------------  ---------------  -----------------------  -------------------
sandbox          replica  2              2                1                        1
sandbox-primary  primary  1              1                1                        0

Instances status
Name       Current LSN  Replication role  Status  QoS         Manager Version  Node
----       -----------  ----------------  ------  ---         ---------------  ----
sandbox-1  0/6053720    Primary           OK      BestEffort  1.25.0-rc1           k8s-eu-worker
sandbox-2  0/6053720    Standby (async)   OK      BestEffort  1.25.0-rc1           k8s-eu-worker2
sandbox-3  0/6053720    Standby (async)   OK      BestEffort  1.25.0-rc1           k8s-eu-worker

With an additional -v (e.g. kubectl cnpg status sandbox -v -v), you can also view PostgreSQL configuration, HBA settings, and certificates.

The command also supports output in yaml and json format.

Promote

The meaning of this command is to promote a pod in the cluster to primary, so you can start with maintenance work or test a switch-over situation in your cluster:

kubectl cnpg promote CLUSTER CLUSTER-INSTANCE

Or you can use the instance node number to promote:

kubectl cnpg promote CLUSTER INSTANCE

Certificates

Clusters created using the CloudNativePG operator work with a CA to sign a TLS authentication certificate.

To get a certificate, you need to provide a name for the secret to store the credentials, the cluster name, and a user for this certificate:

kubectl cnpg certificate cluster-cert --cnpg-cluster CLUSTER --cnpg-user USER

After the secret it's created, you can get it using kubectl:

kubectl get secret cluster-cert

And the content of the same in plain text using the following commands:

kubectl get secret cluster-cert -o json | jq -r '.data | map(@base64d) | .[]'

Restart

The kubectl cnpg restart command can be used in two cases:

  • requesting the operator to orchestrate a rollout restart for a certain cluster. This is useful to apply configuration changes to cluster dependent objects, such as ConfigMaps containing custom monitoring queries.

  • request a single instance restart, either in-place if the instance is the cluster's primary or deleting and recreating the pod if it is a replica.

# this command will restart a whole cluster in a rollout fashion
kubectl cnpg restart CLUSTER

# this command will restart a single instance, according to the policy above
kubectl cnpg restart CLUSTER INSTANCE

If the in-place restart is requested but the change cannot be applied without a switchover, the switchover will take precedence over the in-place restart. A common case for this will be a minor upgrade of PostgreSQL image.

Note

If you want ConfigMaps and Secrets to be automatically reloaded by instances, you can add a label with key cnpg.io/reload to it.

Reload

The kubectl cnpg reload command requests the operator to trigger a reconciliation loop for a certain cluster. This is useful to apply configuration changes to cluster dependent objects, such as ConfigMaps containing custom monitoring queries.

The following command will reload all configurations for a given cluster:

kubectl cnpg reload CLUSTER

Maintenance

The kubectl cnpg maintenance command helps to modify one or more clusters across namespaces and set the maintenance window values, it will change the following fields:

  • .spec.nodeMaintenanceWindow.inProgress
  • .spec.nodeMaintenanceWindow.reusePVC

Accepts as argument set and unset using this to set the inProgress to true in case setand to false in case of unset.

By default, reusePVC is always set to false unless the --reusePVC flag is passed.

The plugin will ask for a confirmation with a list of the cluster to modify and their new values, if this is accepted this action will be applied to all the cluster in the list.

If you want to set in maintenance all the PostgreSQL in your Kubernetes cluster, just need to write the following command:

kubectl cnpg maintenance set --all-namespaces

And you'll have the list of all the cluster to update

The following are the new values for the clusters
Namespace  Cluster Name     Maintenance  reusePVC
---------  ------------     -----------  --------
default    cluster-example  true         false
default    pg-backup        true         false
test       cluster-example  true         false
Do you want to proceed? [y/n]: y

Report

The kubectl cnpg report command bundles various pieces of information into a ZIP file. It aims to provide the needed context to debug problems with clusters in production.

It has two sub-commands: operator and cluster.

report Operator

The operator sub-command requests the operator to provide information regarding the operator deployment, configuration and events.

Important

All confidential information in Secrets and ConfigMaps is REDACTED. The Data map will show the keys but the values will be empty. The flag -S / --stopRedaction will defeat the redaction and show the values. Use only at your own risk, this will share private data.

Note

By default, operator logs are not collected, but you can enable operator log collection with the --logs flag

  • deployment information: the operator Deployment and operator Pod
  • configuration: the Secrets and ConfigMaps in the operator namespace
  • events: the Events in the operator namespace
  • webhook configuration: the mutating and validating webhook configurations
  • webhook service: the webhook service
  • logs: logs for the operator Pod (optional, off by default) in JSON-lines format

The command will generate a ZIP file containing various manifest in YAML format (by default, but settable to JSON with the -o flag). Use the -f flag to name a result file explicitly. If the -f flag is not used, a default time-stamped filename is created for the zip file.

Note

The report plugin obeys kubectl conventions, and will look for objects constrained by namespace. The CNPG Operator will generally not be installed in the same namespace as the clusters. E.g. the default installation namespace is cnpg-system

kubectl cnpg report operator -n cnpg-system

results in

Successfully written report to "report_operator_<TIMESTAMP>.zip" (format: "yaml")

With the -f flag set:

kubectl cnpg report operator -n cnpg-system -f reportRedacted.zip

Unzipping the file will produce a time-stamped top-level folder to keep the directory tidy:

unzip reportRedacted.zip

will result in:

Archive:  reportRedacted.zip
   creating: report_operator_<TIMESTAMP>/
   creating: report_operator_<TIMESTAMP>/manifests/
  inflating: report_operator_<TIMESTAMP>/manifests/deployment.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/operator-pod.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/events.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/validating-webhook-configuration.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/mutating-webhook-configuration.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/webhook-service.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/cnpg-ca-secret.yaml
  inflating: report_operator_<TIMESTAMP>/manifests/cnpg-webhook-cert.yaml

If you activated the --logs option, you'd see an extra subdirectory:

Archive:  report_operator_<TIMESTAMP>.zip
  <snipped …>
  creating: report_operator_<TIMESTAMP>/operator-logs/
  inflating: report_operator_<TIMESTAMP>/operator-logs/cnpg-controller-manager-66fb98dbc5-pxkmh-logs.jsonl

Note

The plugin will try to get the PREVIOUS operator's logs, which is helpful when investigating restarted operators. In all cases, it will also try to get the CURRENT operator logs. If current and previous logs are available, it will show them both.

====== Begin of Previous Log =====
2023-03-28T12:56:41.251711811Z {"level":"info","ts":"2023-03-28T12:56:41Z","logger":"setup","msg":"Starting CloudNativePG Operator","version":"1.25.0-rc1","build":{"Version":"1.25.0-rc1+dev107","Commit":"cc9bab17","Date":"2023-03-28"}}
2023-03-28T12:56:41.251851909Z {"level":"info","ts":"2023-03-28T12:56:41Z","logger":"setup","msg":"Starting pprof HTTP server","addr":"0.0.0.0:6060"}
  <snipped …>

====== End of Previous Log =====
2023-03-28T12:57:09.854306024Z {"level":"info","ts":"2023-03-28T12:57:09Z","logger":"setup","msg":"Starting CloudNativePG Operator","version":"1.25.0-rc1","build":{"Version":"1.25.0-rc1+dev107","Commit":"cc9bab17","Date":"2023-03-28"}}
2023-03-28T12:57:09.854363943Z {"level":"info","ts":"2023-03-28T12:57:09Z","logger":"setup","msg":"Starting pprof HTTP server","addr":"0.0.0.0:6060"}

If the operator hasn't been restarted, you'll still see the ====== Begin … and ====== End … guards, with no content inside.

You can verify that the confidential information is REDACTED by default:

cd report_operator_<TIMESTAMP>/manifests/
head cnpg-ca-secret.yaml

data:
  ca.crt: ""
  ca.key: ""
metadata:
  creationTimestamp: "2022-03-22T10:42:28Z"
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:

With the -S (--stopRedaction) option activated, secrets are shown:

kubectl cnpg report operator -n cnpg-system -f reportNonRedacted.zip -S

You'll get a reminder that you're about to view confidential information:

WARNING: secret Redaction is OFF. Use it with caution
Successfully written report to "reportNonRedacted.zip" (format: "yaml")

unzip reportNonRedacted.zip
head cnpg-ca-secret.yaml

data:
  ca.crt: LS0tLS1CRUdJTiBD…
  ca.key: LS0tLS1CRUdJTiBF…
metadata:
  creationTimestamp: "2022-03-22T10:42:28Z"
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1

report Cluster

The cluster sub-command gathers the following:

  • cluster resources: the cluster information, same as kubectl get cluster -o yaml
  • cluster pods: pods in the cluster namespace matching the cluster name
  • cluster jobs: jobs, if any, in the cluster namespace matching the cluster name
  • events: events in the cluster namespace
  • pod logs: logs for the cluster Pods (optional, off by default) in JSON-lines format
  • job logs: logs for the Pods created by jobs (optional, off by default) in JSON-lines format

The cluster sub-command accepts the -f and -o flags, as the operator does. If the -f flag is not used, a default timestamped report name will be used. Note that the cluster information does not contain configuration Secrets / ConfigMaps, so the -S is disabled.

Note

By default, cluster logs are not collected, but you can enable cluster log collection with the --logs flag

Usage:

kubectl cnpg report cluster CLUSTER [flags]

Note that, unlike the operator sub-command, for the cluster sub-command you need to provide the cluster name, and very likely the namespace, unless the cluster is in the default one.

kubectl cnpg report cluster CLUSTER -f report.zip [-n NAMESPACE]

and then:

unzip report.zip

Archive:  report.zip
   creating: report_cluster_example_<TIMESTAMP>/
   creating: report_cluster_example_<TIMESTAMP>/manifests/
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster-pods.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster-jobs.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/events.yaml

Remember that you can use the --logs flag to add the pod and job logs to the ZIP.

kubectl cnpg report cluster CLUSTER [-n NAMESPACE] --logs

will result in:

Successfully written report to "report_cluster_example_<TIMESTAMP>.zip" (format: "yaml")

unzip report_cluster_<TIMESTAMP>.zip

Archive:  report_cluster_example_<TIMESTAMP>.zip
   creating: report_cluster_example_<TIMESTAMP>/
   creating: report_cluster_example_<TIMESTAMP>/manifests/
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster-pods.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/cluster-jobs.yaml
  inflating: report_cluster_example_<TIMESTAMP>/manifests/events.yaml
   creating: report_cluster_example_<TIMESTAMP>/logs/
  inflating: report_cluster_example_<TIMESTAMP>/logs/cluster-example-full-1.jsonl
   creating: report_cluster_example_<TIMESTAMP>/job-logs/
  inflating: report_cluster_example_<TIMESTAMP>/job-logs/cluster-example-full-1-initdb-qnnvw.jsonl
  inflating: report_cluster_example_<TIMESTAMP>/job-logs/cluster-example-full-2-join-tvj8r.jsonl

Logs

The kubectl cnpg logs command allows to follow the logs of a collection of pods related to CloudNativePG in a single go.

It has at the moment one available sub-command: cluster.

Cluster logs

The cluster sub-command gathers all the pod logs for a cluster in a single stream or file. This means that you can get all the pod logs in a single terminal window, with a single invocation of the command.

As in all the cnpg plugin sub-commands, you can get instructions and help with the -h flag:

kubectl cnpg logs cluster -h

The logs command will display logs in JSON-lines format, unless the --timestamps flag is used, in which case, a human-readable timestamp will be prepended to each line. In this case, lines will no longer be valid JSON, and tools such as jq may not work as desired.

If the logs cluster sub-command is given the -f flag (aka --follow), it will follow the cluster pod logs, and will also watch for any new pods created in the cluster after the command has been invoked. Any new pods found, including pods that have been restarted or re-created, will also have their pods followed. The logs will be displayed in the terminal's standard-out. This command will only exit when the cluster has no more pods left, or when it is interrupted by the user.

If logs is called without the -f option, it will read the logs from all cluster pods until the time of invocation and display them in the terminal's standard-out, then exit. The -o or --output flag can be provided, to specify the name of the file where the logs should be saved, instead of displaying over standard-out. The --tail flag can be used to specify how many log lines will be retrieved from each pod in the cluster. By default, the logs cluster sub-command will display all the logs from each pod in the cluster. If combined with the "follow" flag -f, the number of logs specified by --tail will be retrieved until the current time, and from then the new logs will be followed.

NOTE: unlike other cnpg plugin commands, the -f is used to denote "follow" rather than specify a file. This keeps with the convention of kubectl logs, which takes -f to mean the logs should be followed.

Usage:

kubectl cnpg logs cluster CLUSTER [flags]

Using the -f option to follow:

kubectl cnpg report cluster CLUSTER -f

Using --tail option to display 3 lines from each pod and the -f option to follow:

kubectl cnpg report cluster CLUSTER -f --tail 3

{"level":"info","ts":"2023-06-30T13:37:33Z","logger":"postgres","msg":"2023-06-30 13:37:33.142 UTC [26] LOG:  ending log output to stderr","source":"/controller/log/postgres","logging_pod":"cluster-example-3"}
{"level":"info","ts":"2023-06-30T13:37:33Z","logger":"postgres","msg":"2023-06-30 13:37:33.142 UTC [26] HINT:  Future log output will go to log destination \"csvlog\".","source":"/controller/log/postgres","logging_pod":"cluster-example-3"}
…
…

With the -o option omitted, and with --output specified:

$ kubectl cnpg logs cluster CLUSTER --output my-cluster.log

Successfully written logs to "my-cluster.log"

Pretty

The pretty sub-command reads a log stream from standard input, formats it into a human-readable output, and attempts to sort the entries by timestamp.

It can be used in combination with kubectl cnpg logs cluster, as shown in the following example:

$ kubectl cnpg logs cluster cluster-example | kubectl cnpg logs pretty
2024-10-15T17:35:00.336 INFO     cluster-example-1 instance-manager Starting CloudNativePG Instance Manager
2024-10-15T17:35:00.336 INFO     cluster-example-1 instance-manager Checking for free disk space for WALs before starting PostgreSQL
2024-10-15T17:35:00.347 INFO     cluster-example-1 instance-manager starting tablespace manager
2024-10-15T17:35:00.347 INFO     cluster-example-1 instance-manager starting external server manager
[...]

Alternatively, it can be used in combination with other commands that produce CNPG logs in JSON format, such as stern, or kubectl logs, as in the following example:

$ kubectl logs cluster-example-1 | kubectl cnpg logs pretty
2024-10-15T17:35:00.336 INFO     cluster-example-1 instance-manager Starting CloudNativePG Instance Manager
2024-10-15T17:35:00.336 INFO     cluster-example-1 instance-manager Checking for free disk space for WALs before starting PostgreSQL
2024-10-15T17:35:00.347 INFO     cluster-example-1 instance-manager starting tablespace manager
2024-10-15T17:35:00.347 INFO     cluster-example-1 instance-manager starting external server manager
[...]

The pretty sub-command also supports advanced log filtering, allowing users to display logs for specific pods or loggers, or to filter logs by severity level. Here's an example:

$ kubectl cnpg logs cluster cluster-example | kubectl cnpg logs pretty --pods cluster-example-1 --loggers postgres --log-level info
2024-10-15T17:35:00.509 INFO     cluster-example-1 postgres         2024-10-15 17:35:00.509 UTC [29] LOG:  redirecting log output to logging collector process
2024-10-15T17:35:00.509 INFO     cluster-example-1 postgres         2024-10-15 17:35:00.509 UTC [29] HINT:  Future log output will appear in directory "/controller/log"...
2024-10-15T17:35:00.510 INFO     cluster-example-1 postgres         2024-10-15 17:35:00.509 UTC [29] LOG:  ending log output to stderr
2024-10-15T17:35:00.510 INFO     cluster-example-1 postgres         ending log output to stderr
[...]

The pretty sub-command will try to sort the log stream, to make logs easier to reason about. In order to achieve this, it gathers the logs into groups, and within groups it sorts by timestamp. This is the only way to sort interactively, as pretty may be piped from a command in "follow" mode. The sub-command will add a group separator line, ---, at the end of each sorted group. The size of the grouping can be configured via the --sorting-group-size flag (default: 1000), as illustrated in the following example:

$ kubectl cnpg logs cluster cluster-example | kubectl cnpg logs pretty --sorting-group-size=3
2024-10-15T17:35:20.426 INFO     cluster-example-2 instance-manager Starting CloudNativePG Instance Manager
2024-10-15T17:35:20.426 INFO     cluster-example-2 instance-manager Checking for free disk space for WALs before starting PostgreSQL
2024-10-15T17:35:20.438 INFO     cluster-example-2 instance-manager starting tablespace manager
---
2024-10-15T17:35:20.438 INFO     cluster-example-2 instance-manager starting external server manager
2024-10-15T17:35:20.438 INFO     cluster-example-2 instance-manager starting controller-runtime manager
2024-10-15T17:35:20.439 INFO     cluster-example-2 instance-manager Starting EventSource
---
[...]

To explore all available options, use the -h flag for detailed explanations of the supported flags and their usage.

Info

You can also increase the verbosity of the log by adding more -v options.

Destroy

The kubectl cnpg destroy command helps remove an instance and all the associated PVCs from a Kubernetes cluster.

The optional --keep-pvc flag, if specified, allows you to keep the PVCs, while removing all metadata.ownerReferences that were set by the instance. Additionally, the cnpg.io/pvcStatus label on the PVCs will change from ready to detached to signify that they are no longer in use.

Running again the command without the --keep-pvc flag will remove the detached PVCs.

Usage:

kubectl cnpg destroy CLUSTER INSTANCE

The following example removes the cluster-example-2 pod and the associated PVCs:

kubectl cnpg destroy cluster-example 2

Cluster hibernation

Sometimes you may want to suspend the execution of a CloudNativePG Cluster while retaining its data, then resume its activity at a later time. We've called this feature cluster hibernation.

Hibernation is only available via the kubectl cnpg hibernate [on|off] commands.

Hibernating a CloudNativePG cluster means destroying all the resources generated by the cluster, except the PVCs that belong to the PostgreSQL primary instance.

You can hibernate a cluster with:

kubectl cnpg hibernate on CLUSTER

This will:

  1. shutdown every PostgreSQL instance
  2. detach the PVCs containing the data of the primary instance, and annotate them with the latest database status and the latest cluster configuration
  3. delete the Cluster resource, including every generated resource - except the aforementioned PVCs

When hibernated, a CloudNativePG cluster is represented by just a group of PVCs, in which the one containing the PGDATA is annotated with the latest available status, including content from pg_controldata.

Warning

A cluster having fenced instances cannot be hibernated, as fencing is part of the hibernation procedure too.

In case of error the operator will not be able to revert the procedure. You can still force the operation with:

kubectl cnpg hibernate on CLUSTER --force

A hibernated cluster can be resumed with:

kubectl cnpg hibernate off CLUSTER

Once the cluster has been hibernated, it's possible to show the last configuration and the status that PostgreSQL had after it was shut down. That can be done with:

kubectl cnpg hibernate status CLUSTER

Benchmarking the database with pgbench

Pgbench can be run against an existing PostgreSQL cluster with following command:

kubectl cnpg pgbench CLUSTER -- --time 30 --client 1 --jobs 1

Refer to the Benchmarking pgbench section for more details.

Benchmarking the storage with fio

fio can be run on an existing storage class with following command:

kubectl cnpg fio FIO_JOB_NAME [-n NAMESPACE]

Refer to the Benchmarking fio section for more details.

Requesting a new physical backup

The kubectl cnpg backup command requests a new physical backup for an existing Postgres cluster by creating a new Backup resource.

The following example requests an on-demand backup for a given cluster:

kubectl cnpg backup CLUSTER

or, if using volume snapshots:

kubectl cnpg backup CLUSTER -m volumeSnapshot

The created backup will be named after the request time:

$ kubectl cnpg backup cluster-example
backup/cluster-example-20230121002300 created

By default, a newly created backup will use the backup target policy defined in the cluster to choose which instance to run on. However, you can override this policy with the --backup-target option.

In the case of volume snapshot backups, you can also use the --online option to request an online/hot backup or an offline/cold one: additionally, you can also tune online backups by explicitly setting the --immediate-checkpoint and --wait-for-archive options.

The "Backup" section contains more information about the configuration settings.

Launching psql

The kubectl cnpg psql CLUSTER command starts a new PostgreSQL interactive front-end process (psql) connected to an existing Postgres cluster, as if you were running it from the actual pod. This means that you will be using the postgres user.

Important

As you will be connecting as postgres user, in production environments this method should be used with extreme care, by authorized personnel only.

$ kubectl cnpg psql cluster-example

psql (17.2 (Debian 17.2-1.pgdg110+1))
Type "help" for help.

postgres=#

By default, the command will connect to the primary instance. The user can select to work against a replica by using the --replica option:

$ kubectl cnpg psql --replica cluster-example

psql (17.2 (Debian 17.2-1.pgdg110+1))

Type "help" for help.

postgres=# select pg_is_in_recovery();
 pg_is_in_recovery
-------------------
 t
(1 row)

postgres=# \q

This command will start kubectl exec, and the kubectl executable must be reachable in your PATH variable to correctly work.

Snapshotting a Postgres cluster

Warning

The kubectl cnpg snapshot command has been removed. Please use the backup command to request backups using volume snapshots.

Using pgAdmin4 for evaluation/demonstration purposes only

pgAdmin stands as the most popular and feature-rich open-source administration and development platform for PostgreSQL. For more information on the project, please refer to the official documentation.

Given that the pgAdmin Development Team maintains official Docker container images, you can install pgAdmin in your environment as a standard Kubernetes deployment.

Important

Deployment of pgAdmin in Kubernetes production environments is beyond the scope of this document and, more broadly, of the CloudNativePG project.

However, for the purposes of demonstration and evaluation, CloudNativePG offers a suitable solution. The cnpg plugin implements the pgadmin4 command, providing a straightforward method to connect to a given database Cluster and navigate its content in a local environment such as kind.

For example, you can install a demo deployment of pgAdmin4 for the cluster-example cluster as follows:

kubectl cnpg pgadmin4 cluster-example

This command will produce:

ConfigMap/cluster-example-pgadmin4 created
Deployment/cluster-example-pgadmin4 created
Service/cluster-example-pgadmin4 created
Secret/cluster-example-pgadmin4 created

[...]

After deploying pgAdmin, forward the port using kubectl and connect through your browser by following the on-screen instructions.

Screenshot of desktop installation of pgAdmin

As usual, you can use the --dry-run option to generate the YAML file:

kubectl cnpg pgadmin4 --dry-run cluster-example

pgAdmin4 can be installed in either desktop or server mode, with the default being server.

In server mode, authentication is required using a randomly generated password, and users must manually specify the database to connect to.

On the other hand, desktop mode initiates a pgAdmin web interface without requiring authentication. It automatically connects to the app database as the app user, making it ideal for quick demos, such as on a local deployment using kind:

kubectl cnpg pgadmin4 --mode desktop cluster-example

After concluding your demo, ensure the termination of the pgAdmin deployment by executing:

kubectl cnpg pgadmin4 --dry-run cluster-example | kubectl delete -f -

Warning

Never deploy pgAdmin in production using the plugin.

Logical Replication Publications

The cnpg publication command group is designed to streamline the creation and removal of PostgreSQL logical replication publications. Be aware that these commands are primarily intended for assisting in the creation of logical replication publications, particularly on remote PostgreSQL databases.

Warning

It is crucial to have a solid understanding of both the capabilities and limitations of PostgreSQL's native logical replication system before using these commands. In particular, be mindful of the logical replication restrictions.

Creating a new publication

To create a logical replication publication, use the cnpg publication create command. The basic structure of this command is as follows:

kubectl cnpg publication create \
  --publication PUBLICATION_NAME \
  [--external-cluster EXTERNAL_CLUSTER]
  LOCAL_CLUSTER [options]

There are two primary use cases:

  • With --external-cluster: Use this option to create a publication on an external cluster (i.e. defined in the externalClusters stanza). The commands will be issued from the LOCAL_CLUSTER, but the publication will be for the data in EXTERNAL_CLUSTER.

  • Without --external-cluster: Use this option to create a publication in the LOCAL_CLUSTER PostgreSQL Cluster (by default, the app database).

Warning

When connecting to an external cluster, ensure that the specified user has sufficient permissions to execute the CREATE PUBLICATION command.

You have several options, similar to the CREATE PUBLICATION command, to define the group of tables to replicate. Notable options include:

  • If you specify the --all-tables option, you create a publication FOR ALL TABLES.
  • Alternatively, you can specify multiple occurrences of:
  • --table: Add a specific table (with an expression) to the publication.
  • --schema: Include all tables in the specified database schema (available from PostgreSQL 15).

The --dry-run option enables you to preview the SQL commands that the plugin will execute.

For additional information and detailed instructions, type the following command:

kubectl cnpg publication create --help
Example

Given a source-cluster and a destination-cluster, we would like to create a publication for the data on source-cluster. The destination-cluster has an entry in the externalClusters stanza pointing to source-cluster.

We can run:

kubectl cnpg publication create destination-cluster  \
  --external-cluster=source-cluster --all-tables

which will create a publication for all tables on source-cluster, running the SQL commands on the destination-cluster.

Or instead, we can run:

kubectl cnpg publication create source-cluster \
  --publication=app --all-tables

which will create a publication named app for all the tables in the source-cluster, running the SQL commands on the source cluster.

Info

There are two sample files that have been provided for illustration and inspiration: logical-source and logical-destination.

Dropping a publication

The cnpg publication drop command seamlessly complements the create command by offering similar key options, including the publication name, cluster name, and an optional external cluster. You can drop a PUBLICATION with the following command structure:

kubectl cnpg publication drop \
  --publication PUBLICATION_NAME \
  [--external-cluster EXTERNAL_CLUSTER]
  LOCAL_CLUSTER [options]

To access further details and precise instructions, use the following command:

kubectl cnpg publication drop --help

Logical Replication Subscriptions

The cnpg subscription command group is a dedicated set of commands designed to simplify the creation and removal of PostgreSQL logical replication subscriptions. These commands are specifically crafted to aid in the establishment of logical replication subscriptions, especially when dealing with remote PostgreSQL databases.

Warning

Before using these commands, it is essential to have a comprehensive understanding of both the capabilities and limitations of PostgreSQL's native logical replication system. In particular, be mindful of the logical replication restrictions.

In addition to subscription management, we provide a helpful command for synchronizing all sequences from the source cluster. While its applicability may vary, this command can be particularly useful in scenarios involving major upgrades or data import from remote servers.

Creating a new subscription

To create a logical replication subscription, use the cnpg subscription create command. The basic structure of this command is as follows:

kubectl cnpg subscription create \
  --subscription SUBSCRIPTION_NAME \
  --publication PUBLICATION_NAME \
  --external-cluster EXTERNAL_CLUSTER \
  LOCAL_CLUSTER [options]

This command configures a subscription directed towards the specified publication in the designated external cluster, as defined in the externalClusters stanza of the LOCAL_CLUSTER.

For additional information and detailed instructions, type the following command:

kubectl cnpg subscription create --help
Example

As in the section on publications, we have a source-cluster and a destination-cluster, and we have already created a publication called app.

The following command:

kubectl cnpg subscription create destination-cluster \
  --external-cluster=source-cluster \
  --publication=app --subscription=app

will create a subscription for app on the destination cluster.

Warning

Prioritize testing subscriptions in a non-production environment to ensure their effectiveness and identify any potential issues before implementing them in a production setting.

Info

There are two sample files that have been provided for illustration and inspiration: logical-source and logical-destination.

Dropping a subscription

The cnpg subscription drop command seamlessly complements the create command. You can drop a SUBSCRIPTION with the following command structure:

kubectl cnpg subcription drop \
  --subscription SUBSCRIPTION_NAME \
  LOCAL_CLUSTER [options]

To access further details and precise instructions, use the following command:

kubectl cnpg subscription drop --help

Synchronizing sequences

One notable constraint of PostgreSQL logical replication, implemented through publications and subscriptions, is the lack of sequence synchronization. This becomes particularly relevant when utilizing logical replication for live database migration, especially to a higher version of PostgreSQL. A crucial step in this process involves updating sequences before transitioning applications to the new database (cutover).

To address this limitation, the cnpg subscription sync-sequences command offers a solution. This command establishes a connection with the source database, retrieves all relevant sequences, and subsequently updates local sequences with matching identities (based on database schema and sequence name).

You can use the command as shown below:

kubectl cnpg subscription sync-sequences \
  --subscription SUBSCRIPTION_NAME \
  LOCAL_CLUSTER

For comprehensive details and specific instructions, utilize the following command:

kubectl cnpg subscription sync-sequences --help
Example

As in the previous sections for publication and subscription, we have a source-cluster and a destination-cluster. The publication and the subscription, both called app, are already present.

The following command will synchronize the sequences involved in the app subscription, from the source cluster into the destination cluster.

kubectl cnpg subscription sync-sequences destination-cluster \
  --subscription=app

Warning

Prioritize testing subscriptions in a non-production environment to guarantee their effectiveness and detect any potential issues before deploying them in a production setting.

Integration with K9s

The cnpg plugin can be easily integrated in K9s, a popular terminal-based UI to interact with Kubernetes clusters.

See k9s/plugins.yml for details.

Permissions required by the plugin

The plugin requires a set of Kubernetes permissions that depends on the command to execute. These permissions may affect resources and sub-resources like Pods, PDBs, PVCs, and enable actions like get, delete, patch. The following table contains the full details:

Command Resource Permissions
backup clusters: get
backups: create
certificate clusters: get
secrets: get,create
destroy pods: get,delete
jobs: delete,list
PVCs: list,delete,update
fencing clusters: get,patch
pods: get
fio PVCs: create
configmaps: create
deployment: create
hibernate clusters: get,patch,delete
pods: list,get,delete
pods/exec: create
jobs: list
PVCs: get,list,update,patch,delete
install none
logs clusters: get
pods: list
pods/log: get
maintenance clusters: get,patch,list
pgadmin4 clusters: get
configmaps: create
deployments: create
services: create
secrets: create
pgbench clusters: get
jobs: create
promote clusters: get
clusters/status: patch
pods: get
psql pods: get,list
pods/exec: create
publication clusters: get
pods: get,list
pods/exec: create
reload clusters: get,patch
report cluster clusters: get
pods: list
pods/log: get
jobs: list
events: list
PVCs: list
report operator configmaps: get
deployments: get
events: list
pods: list
pods/log: get
secrets: get
services: get
mutatingwebhookconfigurations: list1
validatingwebhookconfigurations: list1
If OLM is present on the K8s cluster, also:
clusterserviceversions: list
installplans: list
subscriptions: list
restart clusters: get,patch
pods: get,delete
status clusters: get
pods: list
pods/exec: create
pods/proxy: create
PDBs: list
subscription clusters: get
pods: get,list
pods/exec: create
version none

  1. The permissions are cluster scope ClusterRole resources. ↩↩

Additionally, assigning the list permission on the clusters will enable autocompletion for multiple commands.

Role examples

It is possible to create roles with restricted permissions. The following example creates a role that only has access to the cluster logs:

---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cnpg-log
rules:
  - verbs:
      - get
    apiGroups:
      - postgresql.cnpg.io
    resources:
      - clusters
  - verbs:
      - list
    apiGroups:
      - ''
    resources:
      - pods
  - verbs:
      - get
    apiGroups:
      - ''
    resources:
      - pods/log

The next example shows a role with the minimal permissions required to get the cluster status using the plugin's status command:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cnpg-status
rules:
  - verbs:
      - get
    apiGroups:
      - postgresql.cnpg.io
    resources:
      - clusters
  - verbs:
      - list
    apiGroups:
      - ''
    resources:
      - pods
  - verbs:
      - create
    apiGroups:
      - ''
    resources:
      - pods/exec
  - verbs:
      - create
    apiGroups:
      - ''
    resources:
      - pods/proxy
  - verbs:
      - list
    apiGroups:
      - policy
    resources:
      - poddisruptionbudgets

Important

Keeping the verbs restricted per resources and per apiGroups helps to prevent inadvertently granting more than intended permissions.