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authorLouie S <louie@example.com>2024-01-04 16:20:53 -0500
committerLouie S <louie@example.com>2024-01-04 16:20:53 -0500
commiteb2501259115554ade0febef189bb74ab9fbecd7 (patch)
tree1a7120b61da1c2ad4c24ce04de5b9f3145a9d836
parentf1f8431e89e31caaea2b5fd08397601fd452ce82 (diff)
Watched through ch. 12
-rw-r--r--kubernetes_cheat_sheet.md78
1 files changed, 76 insertions, 2 deletions
diff --git a/kubernetes_cheat_sheet.md b/kubernetes_cheat_sheet.md
index 7c1abf3..00103bc 100644
--- a/kubernetes_cheat_sheet.md
+++ b/kubernetes_cheat_sheet.md
@@ -29,6 +29,20 @@
|`kubectl get nodes` |Get a list of all the installed nodes|
|`kubectl describe node [NAME]` |Get some info about a node |
+### Pod
+
+| | |
+|--------------------------------------|-----------------------------|
+|`kubectl create -f [pod-definition.yml]`|Create a pod |
+|`kubectl run [podname] --image=busybox -- /bin/sh -c "sleep 3600"`|Run a pod (example)|
+|`kubectl get pods` |List the running pods |
+|`kubectl get pods -o wide` |Same but with more info |
+|`kubectl describe pod [podname]` |Show pod info |
+|`kubectl get pod [podname] -o yaml > file.yaml`|Extract the pod definition in YAML and save it to a file|
+|`kubectl exec -it [podname] -- sh` |Interactive mode |
+|`kubectl delete -f [pod-definition.yml]`|Delete a pod |
+|`kubectl delete pod [podname]` |Same using the pod's name |
+
### Misc.
| | |
@@ -105,14 +119,31 @@ Pod definition:
```yaml
apiVersion: v1
+# Object type
kind: Pod
metadata:
name: myapp-pod
namespace: prod
+ # Labels are used to identify, describe and group related sets of objects or resources together
+ labels:
+ app: myapp
+ type: front-end
spec:
containers:
- - name: nginx-container
- - image: nginx
+ - name: nginx-container
+ image: nginx
+ ports:
+ # Listening port
+ - containerPort: 80
+ name: http
+ protocol: TCP
+ # Environment Variables
+ env:
+ - name: DBCON
+ value: connectionstring
+ # Equiv to Docker ENTRYPOINT
+ command: ["/bin/sh", "-c"]
+ args: ["echo ${DBCON}"]
```
---
@@ -149,3 +180,46 @@ spec:
limits.cpu: "5"
limits.memory: 10Gi
```
+
+#### Pod definition
+
+---
+
+### Pod state
+
+| | |
+|------------------------------|----------------------------------------|
+|Pending |Accepted but not yet created |
+|Running |Bound to a node |
+|Succeeded |Exited with status 0 |
+|Failed |All containers exit and at least one exited with non-zero status|
+|Unknown |Communication issues with the pod |
+|CrashLoopBackOff |Started crashed, started again, and then crashed again|
+
+---
+
+### Init Containers
+
+Example pod definition that uses init containers
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+ name: myapp-pod
+ labels:
+ app: myapp
+spec:
+ # App container
+ containers:
+ - name: myapp-container
+ image: busybox
+ # Init containers (these will run before the app container)
+ initContainers:
+ - name: init-myservice
+ image: busybox:1.28
+ command: ['sh', '-c', "until nslookup mysvc.namespace.svc.cluster.local; do echo waiting for my service; sleep 2; done"]
+ - name: init-mydb
+ image: busybox:1.28
+ command: ['sh', '-c', "until lookup mydb.namespace.svc.cluster.local; do echo waiting for mydb; sleep 2; done"]
+```