I am trying to run ActiveMQ in Kubernetes. I want to keep the queues even after the pod is terminated and recreated. So far I got the queues to stay even after pod deletion and recreation. But, there is a catch, it seems to be storing the list of queues one previous.
Ex: I create 3 queues a, b, and c. I delete the pod and its recreated. The queue list is empty. I then go ahead and create queues x and y. When I delete and the pod gets recreated, it loads queues a, b, and c. If I add a queue d to it and pod is recreated, it shows x and y.
I have created a configMap like below and I'm using the config map in my YAML file as well.
kubectl create configmap amq-config-map --from-file=/opt/apache-activemq-
5.15.6/data
apiVersion: apps/v1
kind: Deployment
metadata:
name: activemq-deployment-local
labels:
app: activemq
spec:
replicas: 1
selector:
matchLabels:
app: activemq
template:
metadata:
labels:
app: activemq
spec:
containers:
- name: activemq
image: activemq:1.0
ports:
- containerPort: 8161
volumeMounts:
- name: activemq-data-local
mountPath: /opt/apache-activemq-5.15.6/data
readOnly: false
volumes:
- name: activemq-data-local
persistentVolumeClaim:
claimName: amq-pv-claim-local
- name: config-vol
configMap:
name: amq-config-map
---
apiVersion: v1
kind: Service
metadata:
name: my-service-local
spec:
selector:
app: activemq
ports:
- port: 8161
targetPort: 8161
type: NodePort
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: amq-pv-claim-local
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi
---
kind: PersistentVolume
apiVersion: v1
metadata:
name: amq-pv-claim-local
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 3Gi
accessModes:
- ReadWriteOnce
hostPath:
path: /tmpWhen the pod is recreated, I want the queues to stay the same. I'm almost there, but I need some help.
With this deployment plan, I'm able to have activemq working in a Kubernetes cluster running in AWS. However, I'm still trying to figure out why it does not work for mysql in the same way.
Simply running
kubectl create -f activemq.yaml does the trick. Queues are persistent and even terminating the pod and restarting brings up the queues. They remain until the Persistent volume and claim are removed. With this template, I dont need to explicitly create a volume even.
apiVersion: apps/v1
kind: Deployment
metadata:
name: activemq-deployment
labels:
app: activemq
spec:
replicas: 1
selector:
matchLabels:
app: activemq
template:
metadata:
labels:
app: activemq
spec:
securityContext:
fsGroup: 2000
containers:
- name: activemq
image: activemq:1.0
ports:
- containerPort: 8161
volumeMounts:
- name: activemq-data
mountPath: /opt/apache-activemq-5.15.6/data
readOnly: false
volumes:
- name: activemq-data
persistentVolumeClaim:
claimName: amq-pv-claim
---
apiVersion: v1
kind: Service
metadata:
name: amq-nodeport-service
spec:
selector:
app: activemq
ports:
- port: 8161
targetPort: 8161
type: NodePort
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: amq-pv-claim
spec:
#storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2GiYou might be missing a setting in you volume claim:
kind: PersistentVolume
apiVersion: v1
metadata:
name: amq-pv-claim-local
labels:
type: local
spec:
storageClassName: manual
persistentVolumeReclaimPolicy: Retain
capacity:
storage: 3Gi
accessModes:
- ReadWriteOnce
hostPath:
path: /tmpAlso there is still a good change that this does not work due to the use of hostPath: HostPath means it is stored on the server the volume started. It does not migrate along with the restart of the pod, and can lead to very odd behavior in a pv. Look at using NFS, gluster, or any other cluster file system to store your data in a generically accessible path.
If you use a cloud provider, you can also have auto disk mounts from kubernetes, so you can use gcloud, AWS, Azure, etc to provide the storage for you and be mounted by kubernetes where kubernetes wants it be.