I am fairly new to OpenShift and have been using CRC (Code Ready Containers) for a little while, and now decided to install the single server OpenShift on bare metal using the Assisted-Installer method from https://cloud.redhat.com/blog/deploy-openshift-at-the-edge-with-single-node-openshift and https://console.redhat.com/openshift/assisted-installer/clusters/. This has worked well and I have a functional single-server.
As a single server in a test environment (without NFS available) I need/want to create PersistentVolumes with hostPath (localhost storage) - these work flawlessly in CRC. However on the full install, I run into an issue when mounting PVC's to pods as the pods were not running privileged. I edited the deployment config and added the lines below (within the containers hash)
- resources: {}
...
securityContext:
privileged: true
... however still had errors as the restricted SCC has 'allowPrivilegedContainer: false'. I have done a horrible hack of changing this to true, so adding the lines above to the deployment yaml works. However there must be an easier way as none of these hacks seem present in CRC. I checked and CRC pods run restricted, the restricted SCC has privileged set to false, and the Persistent Volume is also using hostPath. I also do not have to edit the deployment yaml as above in CRC - it just works (tm).
Guidance here shows that the containers must run privileged, however the containers in CRC are running restricted and the SCC still has 'allowPrivilegedContainer: false'. https://docs.openshift.com/container-platform/4.8/storage/persistent_storage/persistent-storage-hostpath.html
An example app creation as below (from the RedHat DO280 course) works without any massaging of privileges or deployment config in CRC, but on a real OS server requires the massaging above. As my server is purely for testing, I would like to make it easier without doing the hackjob and deployment changes above.
oc new-app --name mysql --docker-image registry.access.redhat.com/rhscl/mysql-57-rhel7:5.7
oc create secret generic mysql --from-literal password=r3dh4t123
oc set env deployment mysql --prefix MYSQL_ROOT_ --from secret/mysql
oc set volumes deployment/mysql --name mysql-storage --add --type pvc --claim-size 2Gi --claim-mode rwo --mount-path /var/lib/mysql/data
oc get pods -l deployment=mysql
oc get pvc
Any help appreciated.
EDIT: I have overcome this now by enabling nfs-server and adding entries to /etc/exports. However I'm still interested to understand how CRC manages the above issue when using hostPath
The short answer to this is: don't use hostPath.
You are using hostPath to make use of arbitrary disk space available on the underlying host's volume. hostPath can also be used to read/write any directory path on the underlying host's volume -- which, as you can imagine, should be used with great care.
Have a look at this as an alternative -- https://docs.openshift.com/container-platform/4.8/storage/persistent_storage/persistent-storage-local.html