TIL: force-update k8s deployments

man/kubernetes.md

@@ -1,16 +1,32 @@
 ---
-tags: 
+date created: Wednesday, January 23rd 2019, 7:59:04 pm
+date modified: Tuesday, January 2nd 2024, 9:53:05 am
+tags:
   - k8s
   - kubernetes
-date created: Wednesday, January 23rd 2019, 7:59:04 pm
-date modified: Sunday, July 31st 2022, 9:27:38 am
 title: kubernetes / k8s
 ---
 
 # kubernetes / k8s
 
 this is going to be a big one. see also [kubectl](/man/kubectl/)
 
+## default hostname
+
+this is for my future self, if you want to access services between deployments/pods:
+
+```shell
+<service-name>.<namespace>.svc.cluster.local
+```
+
+## get logs from all pods part of deployment
+
+…use labels:
+
+```shell
+kubectl logs -f -l app=name
+```
+
 ## rancher, canal, flannel listen on network interface
 
 I use wireguard to tunnel traffic between kubernetes nodes. When setting up a new *rancher* cluster, you can put in all your information in a GUI, set canal as the default network driver. afterwards **edit the YAML** part and go look for `network`. in there you can change the networking interface for the driver
@@ -26,6 +42,14 @@ network:
 
 the `iface` part is important
 
+## re-deploy kubernetes pods / deployment
+
+say, you have a deployment running and set it to *Always* pull an image, but to trigger this you need to redeploy it. let's also say, you're lazy and don't have a fully featured ci/cd pipeline for your raspberry pi kubernetes cluster at home. so let's just do this to re-deploy your stuff and force a re-download of the image
+
+```shell
+kubectl rollout restart deploy <deployment-name>
+```
+
 ## reisze aws-ebs
 
 * [some sources, most of it was mine](https://kubernetes.io/blog/2018/07/12/resizing-persistent-volumes-using-kubernetes/) | [even more here](https://akomljen.com/easy-way-to-resize-kubernetes-persistent-volumes/)
@@ -96,56 +120,48 @@ afterwards you can delete the pod to re-create it (if you've got a replicaset ho
 kubectl delete pod gitlab-redis-7b9d4587f8-v8jgw
 ```
 
-## suspend all cronjobs
-
-to disable / suspend all cronjobs, do this:
-
-```
-kubectl get cronjobs | grep False | cut -d' ' -f 1 | xargs kubectl patch cronjobs -p '{"spec" : {"suspend" : true }}'
-```
-
-re-enable like this:
+## run one-off cronjob immediately
 
 ```
-kubectl get cronjobs | grep True | cut -d' ' -f 1 | xargs kubectl patch cronjobs -p '{"spec" : {"suspend" : false }}'
+kubectl create job --from=cronjob/your-configured-cron your-cron-manual
 ```
 
-[source](https://stackoverflow.com/a/55090194/10272994)
+## stop kubernetes deployment
 
-## run one-off cronjob immediately
+set the replicas to 0, it'll delete the pods and the deployment will stay intact.
 
 ```
-kubectl create job --from=cronjob/your-configured-cron your-cron-manual
+kubectl scale --replicas=0 deployment <deployment-name>
 ```
 
-## re-deploy kubernetes pods / deployment
+## suspend all cronjobs
 
-say, you have a deployment running and set it to *Always* pull an image, but to trigger this you need to redeploy it. let's also say, you're lazy and don't have a fully featured ci/cd pipeline for your raspberry pi kubernetes cluster at home. so let's just do this to re-deploy your stuff and force a re-download of the image
+to disable / suspend all cronjobs, do this:
 
-```shell
-kubectl rollout restart deploy <deployment-name>
+```
+kubectl get cronjobs | grep False | cut -d' ' -f 1 | xargs kubectl patch cronjobs -p '{"spec" : {"suspend" : true }}'
 ```
 
-## stop kubernetes deployment
-
-set the replicas to 0, it'll delete the pods and the deployment will stay intact.
+re-enable like this:
 
 ```
-kubectl scale --replicas=0 deployment <deployment-name>
+kubectl get cronjobs | grep True | cut -d' ' -f 1 | xargs kubectl patch cronjobs -p '{"spec" : {"suspend" : false }}'
 ```
 
-## get logs from all pods part of deployment
+[source](https://stackoverflow.com/a/55090194/10272994)
 
-…use labels:
+## force-update images
 
-```shell
-kubectl logs -f -l app=name
-```
-
-## default hostname
+if you're using images with the `:latest` tag or another tag which changes remotely but not by tag name/version, you can configure the *imagePullPolicy* to always pull the image when the pod is being deleted, or the [deployment restarted](#re-deploy%20kubernetes%20pods%20/%20deployment).
 
-this is for my future self, if you want to access services between deployments/pods:
+Here's an example deployment:
 
-```shell
-<service-name>.<namespace>.svc.cluster.local
+```yaml
+kind: Deployment
+spec:
+  template:
+    spec:
+      containers:
+        - image: example:latest
+          imagePullPolicy: Always
 ```