Cleanup check after disk layout understood for arm64

.github/workflows/ci-image-build.yml

@@ -206,3 +206,5 @@ jobs:
           if-no-files-found: 'error'
           retention-days: 2
         if: inputs.upload-mount-cache-artifact == 'true'
+      - name: "Check disk space after build"
+        run: df -H

scripts/ci/make_mnt_writeable.sh

@@ -20,15 +20,10 @@ function make_mnt_writeable {
     echo "Investigating node disks"
     lsblk
     sudo blkid
-    echo "Check that we have expected /mnt to be a separate mount"
-    if ! lsblk | grep -q /mnt; then
-        echo "!!!! /mnt is missing as a separate mount, runner misconfigured!"
-        echo "Creating /mnt drive hoping that it will be enough space to use in /"
-        sudo mkdir -p /mnt/
-    fi
     echo "Checking free space!"
     df -H
     echo "Cleaning /mnt just in case it is not empty"
+    sudo mkdir -p /mnt
     sudo rm -rf /mnt/*
     echo "Checking free space!"
     df -H

scripts/ci/move_docker_to_mnt.sh

@@ -17,25 +17,37 @@
 # under the License.
 function cleanup_runner {
     set -x
-    local target_docker_volume_location="/mnt/var-lib-docker"
-    echo "Checking free space!"
-    df -H
-    # This is faster than docker prune
-    echo "Stopping docker"
-    sudo systemctl stop docker
-    echo "Checking free space!"
-    df -H
-    echo "Cleaning docker"
-    sudo rm -rf /var/lib/docker
-    echo "Checking free space!"
-    df -H
-    echo "Mounting ${target_docker_volume_location} to /var/lib/docker"
-    sudo mkdir -p "${target_docker_volume_location}" /var/lib/docker
-    sudo mount --bind "${target_docker_volume_location}" /var/lib/docker
-    sudo chown -R 0:0 "${target_docker_volume_location}"
-    sudo systemctl start docker
     echo "Checking free space!"
     df -H
+    # Note:
+    # Disk layout on x86_64 (2026-01):
+    # - root (/) on /dev/sdb1 (75G)
+    # - an additional mount as /mnt with 75G on /dev/sda1
+    # It seems that arm64 runners have
+    # - root (/) on /dev/sda1 (75G)
+    # - An un-used nvme with 220G
+    # Hence we only move docker to /mnt on x86_64 where we have a separate /mnt mount
+    # If we get short on disk space on arm64 as well we need to revisit this logic
+    # and make the idle nvme being used as well.
+    if uname -i|grep -q x86_64; then
+        local target_docker_volume_location="/mnt/var-lib-docker"
+        # This is faster than docker prune
+        echo "Stopping docker"
+        sudo systemctl stop docker
+        echo "Checking free space!"
+        df -H
+        echo "Cleaning docker"
+        sudo rm -rf /var/lib/docker
+        echo "Checking free space!"
+        df -H
+        echo "Mounting ${target_docker_volume_location} to /var/lib/docker"
+        sudo mkdir -p "${target_docker_volume_location}" /var/lib/docker
+        sudo mount --bind "${target_docker_volume_location}" /var/lib/docker
+        sudo chown -R 0:0 "${target_docker_volume_location}"
+        sudo systemctl start docker
+        echo "Checking free space!"
+        df -H
+    fi
 }
 
 cleanup_runner