Exec Configuration #

This document walks you through how to configure the Exec feature.

What is an Exec? #

The Exec is a kwok Configuration that allows users to define and simulate exec to a single pod.

The YAML below shows all the fields of an Exec resource:

kind: Exec
apiVersion: kwok.x-k8s.io/v1alpha1
metadata:
  name: <string>
  namespace: <string>
spec:
  execs:
  - containers:
    - <string>
    local:
      workDir: <string>
      envs:
      - name: <string>
        value: <string>

To associate an Exec with a certain pod to be simulated, users must ensure metadata.name and metadata.namespace are inconsistent with the name and namespace of the target pod.

The exec simulation setting of a pod are specified via execs field. The execs field is organized by groups, with each corresponding to a collection of containers that shares a same exec simulation setting. Each group consists of a list of container names (containers) and the shared exec simulation setting (local).

If containers is not given in a group, the usage in that group will be applied to all containers of the target pod.

The local field specifies the local environment to be executed. The workDir field specifies the working directory of the local environment. If not set, the working directory will be the root directory. The envs field specifies the environment variables of the local environment.

ClusterExec #

In addition to simulating a single pod, users can also simulate the resource usage for multiple pods via ClusterExec.

The YAML below shows all the fields of a ClusterExec resource:

kind: ClusterExec
apiVersion: kwok.x-k8s.io/v1alpha1
metadata:
  name: <string>
spec:
  selector:
    matchNamespaces:
    - <string>
    matchNames:
    - <string>
  execs:
  - containers:
    - <string>
    local:
      workDir: <string>
      envs:
      - name: <string>
        value: <string>

Compared to Exec, whose metadata.name and metadata.namespace are required to match the associated pod, ClusterExec has an additional selector field for specifying the target pods to be simulated. matchNamespaces and matchNames are both represented as list，which are designed to take pod collections by different levels:

1. If matchNamespaces is empty, ClusterExec will be applied to all pods that are managed by kwok and whose names listed in matchNames.
2. If matchNames is empty, ClusterExec will be applied to all pods managed by kwok and under namespaces listed in matchNamespaces.
3. If matchNames and matchNamespaces are both unset, ClusterExec will be applied to all pods that kwok manages.

The execs field of ClusterExec has the same semantic with the one in Exec.

Examples #