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To perform maintenance on Ceph that brings Ceph down, all VMs must be stopped beforehand and restarted after maintenance has been finished.

Prerequisite

Have the following command line tools available:

• bash
• curl
• jq - lightweight and flexible command-line JSON processor
• xargs

As an admin user, create an API key and store it to ADMIN_APIKEY environment variable. E.g. export ADMIN_APIKEY=x4g...

Store the API hostname to API_HOST environment variable. E.g. export API_HOST=api.pilw.io

Step by Step Guide

Mark all hypervisors as not accepting workloads so no new resources can be created.

...

cat running_vms.json | jq -r '.[]|.uuid' | \
xargs -n 1 -I {} curl -X POST -H "apikey: $ADMIN_APIKEY" https://$API_HOST/v1/user-resource/admin/vm/stop -d uuid={}

Open VMs panel in admin UI, change Filter by status to have only running and press the Reload button. Keep reloading every once in a while and see how the list gets shorter.

Not all VMs agree to stop. Windows is especially known for not stopping when requested. These VMs must be stopped forcefully.

# There is no harm in sending stop again to VMs that are already stopped. We can reuse the same list.
cat running_vms.json | jq -r '.[]|.uuid' | \
xargs -n 1 -I {} curl -X POST -H "apikey: $ADMIN_APIKEY" https://$API_HOST/v1/user-resource/admin/vm/stop -d uuid={} -d force=True

It is now safe to perform maintenance and bring Ceph offline.

...

curl -sS -X GET -H "apikey: $ADMIN_APIKEY" https://$API_HOST/v1/base-operator/host/list | \
jq -r '.[]|.uuid' | \
xargs -n 1 -I {} curl -X PUT -H "apikey: $ADMIN_APIKEY" https://$API_HOST/v1/base-operator/admin/host_flags -d uuid={} -d is_accepting_workloads=1

Finally, Now start all VMs that were running before.

cat running_vms.json | jq -r '.[]|.uuid' | \
xargs -n 1 -I {} curl -X POST -H "apikey: $ADMIN_APIKEY" https://$API_HOST/v1/user-resource/admin/vm/start -d uuid={}

This process will take some time. Some starts might fail, these need investigation, possibly by the VM owner.

Finally, check the current status of VMs in the running_vms.json file.

cat running_vms.json | jq -r '../start -d uuid={}[]|.uuid' | \
xargs -n 1 -I {} bash -c \
"curl -sS -X GET -H \"apikey: $ADMIN_APIKEY\" https://$API_HOST/v1/user-resource/admin/vm?uuid={} | jq -r '.uuid+\"\t\"+(.user_id|tostring)+\"\t\"+.status'"

The result has three columns:

• VM UUID
• User ID
• VM status

Make note of all VMs that do not have status running. Either try to start the VM again, maybe manually from the UI while impersonating the user or send a notification to the user that their VM was unable to start, they should go and have a look. Virtual Console is useful for troubleshooting VM boot issues.