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additionalContainers

Feature state: 1.0.0

A Pod can have multiple containers running apps within it.

Pods are designed to support multiple cooperating processes (as containers) that form a cohesive unit of service. The containers in a Pod are automatically co-located and co-scheduled on the same physical or virtual machine in the cluster. The containers can share resources and dependencies, communicate with one another, and coordinate when and how they are terminated.

additionalContainers value in Kubedeploy allow for defining one or more additionalContainers that will run alongside main application container.

Note

By default, Kubedeploy does not specify any additionalContainers

Supported additionalContainers values in Kubedeploy (click on the plus sign for more info):

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additionalContainers:
  enabled: false # (1)
  pullPolicy: IfNotPresent # (2)
  resources: {} # (3)
  containers: # (4)
    - name: "busybox-init" # (5)
      repository: busybox # (6)
      tag: "latest" #(7)
      command: ["sh", "-c", "exit 0"] # (8)
      args: [] # (9)
      ports: [] # (10)
      healthcheck:
        enabled: false # (11)
        probes:
          livenessProbe: {}
          readinessProbe: {}
          startupProbe: {}
      resources: {} # (12)
  1. Define if initContainers are enabled.
  2. initContainers image pull policy

  3. (optional) Define initContainers global resource requests and limits. Will be applied to all initContainers if more specific (per container) resource requests and limits are not defined.

    Example

    initContainers:
  resources:
    requests:
      cpu: 0.1
      memory: 128Mi
    limits:
      cpu: 0.2
      memory: 256Mi

  4. (list) Sequential list of initContainers

  5. (required) Define initContainer name
  6. (required) Define initContainer repository
  7. (optional) Define initContainer image tag, defaults to latest if unspecified
  8. (optional) Define custom command for initContainer
  9. (optional) Define custom arguments for initContainer

  10. (optional) Define additionalContainer exposed ports (see: containerPort)

    Example

    additionalContainers:
  enabled: true
  containers:
    - name: busybox
      repository: busybox
      ports:
        - containerPort: 9080
          name: extra
          protocol: TCP

  11. (optional) Enable custom healthcheck probes for additionalContainer

  12. (optional) Define custom resources for this specific additionalContainer

Additional containers can be used to augment application with additional functionality, for example defining extra container metric exporter, or using reverse authenticaton proxy.

Shared values/volumes

additionalContainers will automatically inherit all the environment values set in env, envFrom and volume mounts defined in configMaps, extraSecrets and extraVoumeMounts just as the main container would.

Define additionalContainers that exports metrics

values.yaml
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nameOverride: my-app
image:
  repository: nginx
  tag: latest

ports:
  - containerPort: 80
    name: http
    protocol: TCP

additionalContainers:
  enabled: true
  resources:
    requests:
      cpu: 0.1
      memory: 128Mi
    limits:
      cpu: 0.2
      memory: 256Mi
  containers:
    - name: metrics-exporter
      repository: nginx/nginx-prometheus-exporter
      tag: latest
      args:
        - -nginx.scrape-uri=http://localhost:80/stub_status
      ports:
        - containerPort: 9113
          name: metrics
          protocol: TCP
Deploy command
helm install webapp sysbee/kubedeploy -f values.yaml

See also: