Unable to mount MySQL data volume to Kubernetes Minikube pod - docker

Question

I'm trying to set up a dev environment with Kubernetes via Minikube. I successfully mounted the same volume to the same data dir on the same image with Docker for Mac, but I'm having trouble with Minikube.
Relevant files and logs:
db-pod.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
name: msyql
name: db
namespace: default
spec:
containers:
- name: mysqldev
image: mysql/mysql-server:5.6.32
ports:
- containerPort: 3306
hostPort: 3306
volumeMounts:
- mountPath: "/var/lib/mysql"
name: volumesnew
volumes:
- name: volumesnew
hostPath:
path: "/Users/eric/Volumes/mysql"
kubectl get pods:
NAME READY STATUS RESTARTS AGE
db 0/1 Error 1 3s
kubectl logs db:
2016-08-29 20:05:55 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-08-29 20:05:55 0 [Note] mysqld (mysqld 5.6.32) starting as process 1 ...
2016-08-29 20:05:55 1 [Warning] Setting lower_case_table_names=2 because file system for /var/lib/mysql/ is case insensitive
kubectl describe pods db:
Name: db
Namespace: default
Node: minikubevm/10.0.2.15
Start Time: Wed, 31 Aug 2016 07:48:39 -0700
Labels: name=msyql
Status: Running
IP: 172.17.0.3
Controllers: <none>
Containers:
mysqldev:
Container ID: docker://af0937edcd9aa00ebc278bc8be00bc37d60cbaa403c69f71bc1b378182569d3d
Image: mysql/mysql-server:5.6.32
Image ID: docker://sha256:0fb418d5a10c9632b7ace0f6e7f00ec2b8eb58a451ee77377954fedf6344abc5
Port: 3306/TCP
State: Waiting
Reason: CrashLoopBackOff
Last State: Terminated
Reason: Error
Exit Code: 1
Started: Wed, 31 Aug 2016 07:48:42 -0700
Finished: Wed, 31 Aug 2016 07:48:43 -0700
Ready: False
Restart Count: 1
Environment Variables:
MYSQL_ROOT_PASSWORD: test
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
Volumes:
volumesnew:
Type: HostPath (bare host directory volume)
Path: /Users/eric/Volumes/newmysql
default-token-il74e:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-il74e
QoS Tier: BestEffort
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
7s 7s 1 {default-scheduler } Normal Scheduled Successfully assigned db to minikubevm
6s 6s 1 {kubelet minikubevm} spec.containers{mysqldev} Normal Created Created container with docker id 568f9112dce0
6s 6s 1 {kubelet minikubevm} spec.containers{mysqldev} Normal Started Started container with docker id 568f9112dce0
6s 4s 2 {kubelet minikubevm} spec.containers{mysqldev} Normal Pulled Container image "mysql/mysql-server:5.6.32" already present on machine
4s 4s 1 {kubelet minikubevm} spec.containers{mysqldev} Normal Created Created container with docker id af0937edcd9a
4s 4s 1 {kubelet minikubevm} spec.containers{mysqldev} Normal Started Started container with docker id af0937edcd9a
3s 2s 2 {kubelet minikubevm} spec.containers{mysqldev} Warning BackOff Back-off restarting failed docker container
3s 2s 2 {kubelet minikubevm} Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "mysqldev" with CrashLoopBackOff: "Back-off 10s restarting failed container=mysqldev pod=db_default(012d5178-6f8a-11e6-97e8-c2daf2e2520c)"
I was able to mount the data directory from the host to the container in a test directory, but I'm having trouble mounting to the MySQL data directory. Also, I tried to mount an empty directory to the container's data dir with the appropriate MySQL environment variables set, which in Docker for Mac allowed me to perform a SQL dump in the new dir, but I'm seeing the same errors in Minikube.
Any thought on what might be the cause, or if I'm not setting up my dev environment the preferred Kubernetes/Minikube way, please share your thoughts.

Answer 1

I was able to resolve this with the following:
echo "/Users -network 192.168.99.0 -mask 255.255.255.0 -alldirs -maproot=root:wheel" | sudo tee -a /etc/exports
sudo nfsd restart
minikube start
minikube ssh -- sudo umount /Users
minikube ssh -- sudo /usr/local/etc/init.d/nfs-client start
minikube ssh -- sudo mount 192.168.99.1:/Users /Users -o rw,async,noatime,rsize=32768,wsize=32768,proto=tcp
I am running Minikube in VirtualBox. I don't know if this will work with other VM drivers - xhyve, etc.
Reference: https://github.com/kubernetes/minikube/issues/2
EDIT: I should mention that this works for minikube v0.14.0.

Answer 2

1. Mount the folder you want to share on your host, in minikube:
minikube mount ./path/to/mySharedData:/mnt1/shared1
Don't close the terminal. That process needs to be running all the time for the folder to be accessible.
2. Use that folder with hostPath:
spec:
containers:
- name: mysqldev
image: mysql/mysql-server:5.6.32
ports:
- containerPort: 3306
hostPort: 3306
volumeMounts:
- mountPath: "/var/lib/mysql"
name: my-volume
volumes:
- name: my-volume
hostPath:
path: "/mnt1/shared1"
3. Writing access issue?
In case you have a writing access issue, you might want to mount the volume with:
minikube mount ./path/to/mySharedData:/mnt1/shared1 --uid 10001 --gid 10001
Here, the volume mounted in minikube will have group id and user id 10001. This is the user id of Azure SQL Edge server inside the container.
I don't know which is the user id of mysql in your case. If you want to know, log into your container and type id, it will tell you the user id.