Use loop device for microceph (#826)

See also actions/runner-images#13587.

Fixes #825

Author: friegger

.github/workflows/integration-test.yml

@@ -36,10 +36,14 @@ jobs:
               sudo microceph.ceph osd set $flag
           done
           
-          # Repurpose the ephemeral disk for ceph OSD.
-          sudo swapoff /mnt/swapfile
-          ephemeral_disk="$(findmnt --noheadings --output SOURCE --target /mnt | sed 's/[0-9]\+$//')"
-          sudo microceph disk add --wipe "${ephemeral_disk}"
+          # Create a loop device for Ceph OSD
+          CEPH_OSD_IMG=~/ceph-osd.img
+          CEPH_OSD_SIZE_GIB=10
+          
+          dd if=/dev/zero of="$CEPH_OSD_IMG" bs=1M count=$((CEPH_OSD_SIZE_GIB*1024)) status=progress
+          sync
+          LOOP=$(sudo losetup --find --show "$CEPH_OSD_IMG")
+          sudo microceph disk add --wipe "${LOOP}"
           sudo rm -rf /etc/ceph
           sudo ln -s /var/snap/microceph/current/conf/ /etc/ceph
           sudo microceph enable rgw
@@ -64,7 +68,7 @@ jobs:
           echo "CEPH_USERNAME=admin" >> $GITHUB_ENV
           echo "CEPH_POOLNAME=devpool" >> $GITHUB_ENV
           echo "CEPH_CLIENTNAME=client.admin" >> $GITHUB_ENV
-          echo "CEPH_DISK_SIZE=$(df --output=size -B 1 /mnt | sed -n '2p' | sed 's/[[:blank:]]//g')" >> $GITHUB_ENV
+          echo "CEPH_DISK_SIZE=$((10*1024*1024*1024))" >> $GITHUB_ENV
           echo "CEPH_KEYRING_FILENAME=/etc/ceph/ceph.client.admin.keyring" >> $GITHUB_ENV
           echo "CEPH_MONITORS=$(hostname):6789" >> $GITHUB_ENV
           echo "CEPH_CONFIG_FILE=/etc/ceph/ceph.conf" >> $GITHUB_ENV