CODEWITHSUNDEEP
kubernetesdeployment
Olshansky
Olshansky

Reputation: 6424

What are production uses for Kubernetes pods without an associated deployment?

I have seen the one-pod <-> one-container rule, which seems to apply to business logic pods, but has exceptions when it comes to shared network/volume related resources.

What are encountered production uses of deploying pods without a deployment configuration?

Upvotes: 1

Views: 76

Answers (2)

Fran&#231;ois
Fran&#231;ois

Reputation: 2241

In our case, we use stand alone pods for debugging purposes only. Otherwise you want your configuration to be stateless and written in YAML files.

For instance, debugging the dns resolution: https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/

kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml
kubectl exec -i -t dnsutils -- nslookup kubernetes.default

Upvotes: 2

David Medinets
David Medinets

Reputation: 5618

I use pods directly to start a Centos (or other operating system) container in which to verify connections or test command line options.

As a specific example, below is a shell script that starts an ubuntu container. You can easily modify the manifest to test secret access or change the service account to test access control.

#!/bin/bash

RANDOMIZER=$(uuid | cut -b-5)
POD_NAME="bash-shell-$RANDOMIZER"
IMAGE=ubuntu
NAMESPACE=$(uuid)

kubectl create namespace $NAMESPACE

kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
  name: $POD_NAME
  namespace: $NAMESPACE
spec:
  containers:
  - name: $POD_NAME
    image: $IMAGE
    command: ["/bin/bash"]
    args: ["-c", "while true; do date; sleep 5; done"]
  hostNetwork: true
  dnsPolicy: Default
  restartPolicy: Never
EOF

echo "---------------------------------"
echo "| Press ^C when pod is running. |"
echo "---------------------------------"

kubectl -n $NAMESPACE get pod $POD_NAME -w

echo

kubectl -n $NAMESPACE exec -it $POD_NAME -- /bin/bash

kubectl -n $NAMESPACE delete pod $POD_NAME
kubectl delete namespace $NAMESPACE

Upvotes: 2

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