Difference between revisions of "CKA: Create and configure basic Pods"
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| + | Only available in first CKA versions | ||
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== Create a [[Pod]] == | == Create a [[Pod]] == | ||
* To create a pod based on a yaml definition file: <code>[[kubectl apply]] -f https://k8s.io/examples/pods/storage/redis.yaml</code><ref>https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/</ref> | * To create a pod based on a yaml definition file: <code>[[kubectl apply]] -f https://k8s.io/examples/pods/storage/redis.yaml</code><ref>https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/</ref> | ||
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:<code>[[kubectl apply]] -f https://k8s.io/examples/pods/storage/redis.yaml --namespace=MY_TEST_NAMESPACE</code><ref>https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/</ref> | :<code>[[kubectl apply]] -f https://k8s.io/examples/pods/storage/redis.yaml --namespace=MY_TEST_NAMESPACE</code><ref>https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/</ref> | ||
:To verify container is running: | :To verify container is running: | ||
| − | ::<code>[[kubectl get]] | + | ::<code>[[kubectl get pod]] NAME_POD --namespace=MY_TEST_NAMESPACE</code> |
==Set up a [[Volume]] for a [[Pod]]== | ==Set up a [[Volume]] for a [[Pod]]== | ||
| − | + | Review different Volume types in https://kubernetes.io/docs/concepts/storage/volumes/#types-of-volumes. | |
| − | + | Create a Pod that runs a single Container. This Pod has a Volume of type <code>emptyDir</code> (empty directory) (see [[Volume]] for volume types) that exists throughout the Pod's life cycle, even when the Container is destroyed and restarted. | |
| − | + | Example: | |
| − | Create a Pod that runs a single Container. This Pod has a Volume of type <code>emptyDir</code> (empty directory) (see [[Volume]] for volume types) that exists throughout the Pod's life cycle, even when the Container is destroyed and restarted. | + | <code>pods/storage/redis.yaml</code> |
| − | + | apiVersion: v1 | |
| + | [[kind: Pod]] | ||
| + | metadata: | ||
| + | name: redis | ||
| + | spec: | ||
| + | containers: | ||
| + | - [[name:]] redis | ||
| + | [[image]]: redis | ||
| + | [[volumeMounts]]: | ||
| + | - name: redis-storage | ||
| + | [[mountPath]]: /data/redis | ||
| + | [[volumes:]] | ||
| + | - name: redis-storage | ||
| + | emptyDir: {}</pre> | ||
| − | + | === Steps === | |
| − | + | ==== Create Pod ==== | |
| − | + | :<code>kubectl apply -f https://k8s.io/examples/pods/storage/redis.yaml</code> | |
| − | + | :<code>pod/redis created</code> | |
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| + | ==== Verify [[Pod]] is running ==== | ||
| − | + | [[kubectl get pods]] | |
| − | + | NAME READY STATUS RESTARTS AGE | |
| + | redis 1/1 Running 0 3m29s | ||
| − | + | ==== List all Kubernetes resources created ==== | |
| − | + | [[kubectl get all]] | |
| − | NAME | + | NAME READY STATUS RESTARTS AGE |
| − | redis | + | pod/redis 1/1 Running 0 10m |
| + | |||
| + | NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE | ||
| + | service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d21h | ||
| − | + | ==== In another terminal, open an interactive session inside the Container that is running: ==== | |
<code>[[kubectl exec]] -it redis -- /bin/bash</code> | <code>[[kubectl exec]] -it redis -- /bin/bash</code> | ||
| − | ''' | + | '''5. Create a file in <code>/data/redis</code>''' |
<pre>root@redis:/data# cd /data/redis/ | <pre>root@redis:/data# cd /data/redis/ | ||
root@redis:/data/redis# echo Hello > test-file</pre> | root@redis:/data/redis# echo Hello > test-file</pre> | ||
| − | ''' | + | '''6. List running processes:''' |
<pre>root@redis:/data/redis# apt-get update | <pre>root@redis:/data/redis# apt-get update | ||
root@redis:/data/redis# apt-get install procps | root@redis:/data/redis# apt-get install procps | ||
| Line 89: | Line 99: | ||
== See also == | == See also == | ||
| − | * {{kubectl}} | + | * {{kubectl apply}} |
| − | * | + | * {{CKA versions}} |
| + | * {{CKA}} | ||
{{CC license}} | {{CC license}} | ||
Latest revision as of 16:12, 29 February 2024
Only available in first CKA versions
Contents
Create a Pod[edit]
- To create a pod based on a yaml definition file:
kubectl apply -f https://k8s.io/examples/pods/storage/redis.yaml[1] - To create a pod in a namespace:
kubectl create namespace MY_TEST_NAMESPACEkubectl apply -f https://k8s.io/examples/pods/storage/redis.yaml --namespace=MY_TEST_NAMESPACE[2]- To verify container is running:
kubectl get pod NAME_POD --namespace=MY_TEST_NAMESPACE
Set up a Volume for a Pod[edit]
Review different Volume types in https://kubernetes.io/docs/concepts/storage/volumes/#types-of-volumes.
Create a Pod that runs a single Container. This Pod has a Volume of type emptyDir (empty directory) (see Volume for volume types) that exists throughout the Pod's life cycle, even when the Container is destroyed and restarted.
Example:
pods/storage/redis.yaml
apiVersion: v1 kind: Pod metadata: name: redis spec: containers: - name: redis image: redis volumeMounts: - name: redis-storage mountPath: /data/redis volumes: - name: redis-storage
emptyDir: {}
Steps[edit]
Create Pod[edit]
kubectl apply -f https://k8s.io/examples/pods/storage/redis.yamlpod/redis created
Verify Pod is running[edit]
kubectl get pods NAME READY STATUS RESTARTS AGE redis 1/1 Running 0 3m29s
List all Kubernetes resources created[edit]
kubectl get all NAME READY STATUS RESTARTS AGE pod/redis 1/1 Running 0 10m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d21h
In another terminal, open an interactive session inside the Container that is running:[edit]
kubectl exec -it redis -- /bin/bash
5. Create a file in /data/redis
root@redis:/data# cd /data/redis/ root@redis:/data/redis# echo Hello > test-file
6. List running processes:
root@redis:/data/redis# apt-get update root@redis:/data/redis# apt-get install procps root@redis:/data/redis# ps aux
output:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND redis 1 0.1 0.1 33308 3828 ? Ssl 00:46 0:00 redis-server *:6379 root 12 0.0 0.0 20228 3020 ? Ss 00:47 0:00 /bin/bash root 15 0.0 0.0 17500 2072 ? R+ 00:48 0:00 ps aux
6.In the terminal, kill the Redis process:
root@redis:/data/redis# kill <pid>
where <pid>is the process ID (PID) of Redis.
7.In the original terminal, observe the changes in the Redis Pod. You will eventually see something like the following:
NAME READY STATUS RESTARTS AGE redis 1/1 Running 0 13s redis 0/1 Completed 0 6m redis 1/1 Running 1 6m
At this point, the Container has been destroyed and restarted. This is because the Redis Pod has a restartPolicy (restart policy) of Always(always).
1.Open a terminal in the restarted Container:
kubectl exec -it redis -- /bin/bash
2.In the terminal, go to /data/redisand verify that it test-filestill exists:
root@redis:/data/redis# cd /data/redis/ root@redis:/data/redis# ls test-file
3.Remove the Pod you created for this exercise:
kubectl delete pod redis
Related terms[edit]
See also[edit]
kubectl apply, --server-side, -k, -f, creationTimestamp, kubectl.kubernetes.io/last-applied-configuration, --validate=false- CKA v1.26, CKA v1.27, CKA v1.28
- CKA: v1.28: API, Namespace, Pods, secrets, Services, deployments, nodes, Volumes, Ingress, CKS
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