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Percona Operator for MySQL
Add sidecar containers
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    • Welcome
      • System Requirements
      • Design and architecture
      • Comparison with other solutions
      • Install with Helm
      • Install with kubectl
      • Install on Minikube
      • Install on Google Kubernetes Engine (GKE)
      • Install on Amazon Elastic Kubernetes Service (AWS EKS)
      • Install on Microsoft Azure Kubernetes Service (AKS)
      • Install on OpenShift
      • Generic Kubernetes installation
      • Multi-cluster and multi-region deployment
      • Application and system users
      • Changing MySQL Options
      • Anti-affinity and tolerations
      • Labels and annotations
      • Local Storage support
      • Defining environment variables
      • Load Balancing with HAProxy
      • Load Balancing with ProxySQL
      • Transport Encryption (TLS/SSL)
      • Data at rest encryption
      • Telemetry
      • Backup and restore
      • Upgrade Database and Operator
      • Horizontal and vertical scaling
      • Monitor with Percona Monitoring and Management (PMM)
      • Add sidecar containers
        • Adding a sidecar container
        • Getting shell access to a sidecar container
        • Mount volumes into sidecar containers
          • Persistent Volume
          • Secret
          • configMap
      • Restart or pause the cluster
      • Crash recovery
      • Debug and troubleshoot
      • How to install Percona XtraDB Cluster in multi-namespace (cluster-wide) mode
      • How to upgrade Percona XtraDB Cluster manually
      • How to use private registry
      • Custom Resource options
      • Percona certified images
      • Operator API
      • Frequently Asked Questions
      • Old releases (documentation archive)
      • Release notes index
      • Percona Operator for MySQL based on Percona XtraDB Cluster 1.12.0 (2022-12-07)
      • Percona Operator for MySQL based on Percona XtraDB Cluster 1.11.0 (2022-06-03)
      • Percona Distribution for MySQL Operator 1.10.0 (2021-11-24)
      • Percona Distribution for MySQL Operator 1.9.0 (2021-08-09)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.8.0 (2021-05-26)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.7.0 (2021-02-02)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.6.0 (2020-09-09)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.5.0 (2020-07-21)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.4.0 (2020-04-29)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.3.0 (2020-01-06)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.2.0 (2019-09-20)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.1.0 (2019-07-15)
      • Percona Kubernetes Operator for Percona XtraDB Cluster 1.0.0 (2019-05-29)

    • Adding a sidecar container
    • Getting shell access to a sidecar container
    • Mount volumes into sidecar containers
      • Persistent Volume
      • Secret
      • configMap

    Using sidecar containers¶

    The Operator allows you to deploy additional (so-called sidecar) containers to the Pod. You can use this feature to run debugging tools, some specific monitoring solutions, etc.

    Note

    Custom sidecar containers can easily access other components of your cluster.

    Therefore they should be used carefully and by experienced users only.

    Adding a sidecar container¶

    You can add sidecar containers to Percona XtraDB Cluster, HAProxy, and ProxySQL Pods. Just use sidecars subsection ing the pxc, haproxy, or proxysql section of the deploy/cr.yaml configuration file. In this subsection, you should specify the name and image of your container and possibly a command to run:

    spec:
      pxc:
        ....
        sidecars:
        - image: busybox
          command: ["/bin/sh"]
          args: ["-c", "while true; do echo echo $(date -u) 'test' >> /dev/null; sleep 5; done"]
          name: my-sidecar-1
        ....
    

    Apply your modifications as usual:

    $ kubectl apply -f deploy/cr.yaml
    

    Running kubectl describe command for the appropriate Pod can bring you the information about the newly created container:

    $ kubectl describe pod cluster1-pxc-0
    
    Expected output
    ....
    Containers:
    ....
    my-sidecar-1:
      Container ID:  docker://f0c3437295d0ec819753c581aae174a0b8d062337f80897144eb8148249ba742
      Image:         busybox
      Image ID:      docker-pullable://busybox@sha256:139abcf41943b8bcd4bc5c42ee71ddc9402c7ad69ad9e177b0a9bc4541f14924
      Port:          <none>
      Host Port:     <none>
      Command:
        /bin/sh
      Args:
        -c
        while true; do echo echo $(date -u) 'test' >> /dev/null; sleep 5; done
      State:          Running
        Started:      Thu, 11 Nov 2021 10:38:15 +0300
      Ready:          True
      Restart Count:  0
      Environment:    <none>
      Mounts:
        /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-fbrbn (ro)
    ....
    

    Getting shell access to a sidecar container¶

    You can login to your sidecar container as follows:

    $ kubectl exec -it cluster1-pxc-0 -c my-sidecar-1 -- sh
    / #
    

    Mount volumes into sidecar containers¶

    It is possible to mount volumes into sidecar containers.

    Following subsections describe different volume types, which were tested with sidecar containers and are known to work.

    Persistent Volume¶

    You can use Persistent volumes when you need dynamically provisioned storage which doesn’t depend on the Pod lifecycle. To use such volume, you should claim durable storage with persistentVolumeClaim without specifying any non-important details.

    The following example requests 1G storage with sidecar-volume-claim PersistentVolumeClaim, and mounts the correspondent Persistent Volume to the my-sidecar-1 container’s filesystem under the /volume1 directory:

    ...
    sidecars:
      - image: busybox
        command: ["/bin/sh"]
        args: ["-c", "while true; do echo echo $(date -u) 'test' >> /dev/null; sleep 5; done"]
        name: my-sidecar-1
        volumeMounts:
        - mountPath: /volume1
          name: sidecar-volume-claim
      sidecarPVCs:
      - apiVersion: v1
        kind: PersistentVolumeClaim
        metadata:
          name: sidecar-volume-claim
        spec:
          resources:
            requests:
              storage: 1Gi
          volumeMode: Filesystem
          accessModes:
            - ReadWriteOnce
    

    Secret¶

    You can use a secret volume to pass the information which needs additional protection (e.g. passwords), to the container. Secrets are stored with the Kubernetes API and mounted to the container as RAM-stored files.

    You can mount a secret volume as follows:

    ...
    sidecars:
      - image: busybox
        command: ["/bin/sh"]
        args: ["-c", "while true; do echo echo $(date -u) 'test' >> /dev/null; sleep 5; done"]
        name: my-sidecar-1
        volumeMounts:
        - mountPath: /secret
          name: sidecar-secret
      sidecarVolumes:
      - name: sidecar-secret
        secret:
          secretName: mysecret
    

    The above example creates a sidecar-secret volume (based on already existing mysecret Secret object) and mounts it to the my-sidecar-1 container’s filesystem under the /secret directory.

    Note

    Don’t forget you need to create a Secret Object before you can use it.

    configMap¶

    You can use a configMap volume to pass some configuration data to the container. Secrets are stored with the Kubernetes API and mounted to the container as RAM-stored files.

    You can mount a configMap volume as follows:

    ...
    sidecars:
      - image: busybox
        command: ["/bin/sh"]
        args: ["-c", "while true; do echo echo $(date -u) 'test' >> /dev/null; sleep 5; done"]
        name: my-sidecar-1
        volumeMounts:
        - mountPath: /config
          name: sidecar-config
      sidecarVolumes:
      - name: sidecar-config
        configMap:
          name: myconfigmap
    

    The above example creates a sidecar-config volume (based on already existing myconfigmap configMap object) and mounts it to the my-sidecar-1 container’s filesystem under the /config directory.

    Note

    Don’t forget you need to create a configMap Object before you can use it.

    Contact Us

    For free technical help, visit the Percona Community Forum.

    To report bugs or submit feature requests, open a JIRA ticket.

    For paid support and managed or consulting services , contact Percona Sales.


    Last update: 2023-02-09
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