test: Use tmpfs for all the chroots

Currently /srv is a Docker volume backed by an overlay filesystem on top
of whatever the rootfs block device. The overlay filesystem is slow, so
rather than having tests opt-in to using a ramfs, do this by default for
all tests.

This also simplifies the ramfs logic.

Signed-off-by: Pablo Barbáchano <pablob@amazon.com>

Author: pb8o

.buildkite/pipeline_perf.py

@@ -10,7 +10,7 @@
     "block": {
         "label": "🖴 Block Performance",
         "test_path": "integration_tests/performance/test_block_performance.py",
-        "devtool_opts": "-r 16834m -c 1-10 -m 0",
+        "devtool_opts": "-c 1-10 -m 0",
         "timeout_in_minutes": 240,
     },
     "snapshot-latency": {

tests/conftest.py

@@ -169,7 +169,6 @@ def test_fc_session_root_path():
         prefix="fctest-", dir=defs.DEFAULT_TEST_SESSION_ROOT_PATH
     )
     yield fc_session_root_path
-    shutil.rmtree(fc_session_root_path)
 
 
 @pytest.fixture(scope="session")
@@ -315,6 +314,7 @@ def kill(self):
             for vm in self.vms:
                 vm.kill()
                 vm.jailer.cleanup()
+                shutil.rmtree(vm.jailer.chroot_base_with_id())
             shutil.rmtree(self.tmp_path)
 
     uvm_factory = MicroVMFactory(fc_tmp_path, bin_cloner_path)

tests/framework/jailer.py

@@ -248,9 +248,6 @@ def cleanup(self):
         if self._ramfs_path:
             utils.run_cmd("umount {}".format(self._ramfs_path), ignore_return_code=True)
 
-        if self.jailer_id is not None:
-            shutil.rmtree(self.chroot_base_with_id(), ignore_errors=True)
-
         if self.netns and os.path.exists("/var/run/netns/{}".format(self.netns)):
             try:
                 utils.run_cmd("ip netns del {}".format(self.netns))

tools/devtool

@@ -137,9 +137,6 @@ OPT_UNATTENDED=false
 # Get the target prefix to avoid repeated calls to uname -m
 TARGET_PREFIX="$(uname -m)-unknown-linux-"
 
-DEFAULT_TEST_SESSION_ROOT_PATH=/srv
-DEFAULT_RAMDISK_PATH=/mnt/devtool-ramdisk
-
 
 # Check if Docker is available and exit if it's not.
 # Upon returning from this call, the caller can be certain Docker is available.
@@ -312,6 +309,8 @@ run_devctr() {
         --rm \
         --volume /dev:/dev \
         --volume "$FC_ROOT_DIR:$CTR_FC_ROOT_DIR:z" \
+        --tmpfs /srv:exec,dev,size=32G \
+        -v /boot:/boot \
         --env PYTHONDONTWRITEBYTECODE=1 \
         "$DEVCTR_IMAGE" "${ctr_args[@]}"
 }
@@ -410,11 +409,6 @@ cmd_help() {
     echo "        will be passed through to pytest."
     echo "        -c, --cpuset-cpus cpulist    Set a dedicated cpulist to be used by the tests."
     echo "        -m, --cpuset-mems memlist    Set a dedicated memlist to be used by the tests."
-    echo "        -r, --ramdisk size[k|m|g]    Use a ramdisk of 'size' MB for
-                                               the entire test session (e.g
-                                               stored artifacts, Firecracker
-                                               binaries, logs/metrics FIFOs
-                                               and test created device files)."
     echo ""
 }
 
@@ -511,34 +505,6 @@ cmd_distclean() {
     fi
 }
 
-mount_ramdisk() {
-    local ramdisk_size="$1"
-    umount_ramdisk
-    DEFAULT_RAMDISK_PATH=$(sudo mktemp -d /mnt/devtool-ramdisk.XXXXXX)
-    ok_or_die "Could not create ramdisk directory"
-    sudo mkdir -p ${DEFAULT_RAMDISK_PATH} && \
-    sudo mount -t tmpfs -o size=${ramdisk_size} tmpfs ${DEFAULT_RAMDISK_PATH}
-    ok_or_die "Failed to mount ramdisk to ${DEFAULT_RAMDISK_PATH}. Check the permission."
-    sudo mkdir -p ${DEFAULT_RAMDISK_PATH}/srv
-    sudo mkdir -p  ${DEFAULT_RAMDISK_PATH}/tmp
-
-    say "Using ramdisk: ${DEFAULT_RAMDISK_PATH}"
-}
-
-umount_ramdisk() {
-    if [ ! -e "${DEFAULT_RAMDISK_PATH}" ]; then
-        return 0
-    fi
-    if [ ! -d "${DEFAULT_RAMDISK_PATH}" ]; then
-        die "${DEFAULT_RAMDISK_PATH} is not a directory."
-    fi
-    if [ ! -w "${DEFAULT_RAMDISK_PATH}" ]; then
-        die "Failed to unmount ${DEFAULT_RAMDISK_PATH}. Check the permission."
-    fi
-    sudo umount ${DEFAULT_RAMDISK_PATH} &>/dev/null
-    sudo rmdir ${DEFAULT_RAMDISK_PATH} &>/dev/null
-}
-
 ensure_ci_artifacts() {
     # Fetch all the artifacts so they are local
     say "Fetching CI artifacts from S3"
@@ -570,11 +536,6 @@ cmd_test() {
                 shift
                 local cpuset_mems="$1"
                 ;;
-            "-r"|"--ramdisk")
-                shift
-                local ramdisk_size="$1"
-                local ramdisk=true
-                ;;
             "--")               { shift; break;     } ;;
             *)
                 die "Unknown argument: $1. Please use --help for help."
@@ -594,11 +555,6 @@ cmd_test() {
     say "$(lscpu)"
     say "Starting test run ..."
 
-    if [[ $ramdisk = true ]]; then
-        mount_ramdisk ${ramdisk_size}
-        ramdisk_args="--env TMPDIR=${DEFAULT_TEST_SESSION_ROOT_PATH}/tmp --volume ${DEFAULT_RAMDISK_PATH}:${DEFAULT_TEST_SESSION_ROOT_PATH}"
-    fi
-
     # Testing (running Firecracker via the jailer) needs root access,
     # in order to set-up the Firecracker jail (manipulating cgroups, net
     # namespaces, etc).
@@ -628,19 +584,13 @@ cmd_test() {
         --cpuset-cpus="$cpuset_cpus" \
         --cpuset-mems="$cpuset_mems" \
         --env-file env.list \
-        -v /boot:/boot \
-        ${ramdisk_args} \
         -- \
         ./tools/test.sh "$@"
 
     ret=$?
 
     say "Finished test run ..."
 
-    if [[ $ramdisk = true ]]; then
-        umount_ramdisk
-    fi
-
     # Running as root would have created some root-owned files under the build
     # dir. Let's fix that.
     cmd_fix_perms
@@ -664,12 +614,7 @@ cmd_shell() {
         case "$1" in
             "-h"|"--help")          { cmd_help; exit 1; } ;;
             "-p"|"--privileged")    { privileged=true;  } ;;
-            "-r"|"--ramdisk")
-                  shift
-                  local ramdisk_size="$1"
-                  local ramdisk=true
-                  ;;
-              "--")               { shift; break;     } ;;
+            "--")               { shift; break;     } ;;
             *)
                 die "Unknown argument: $1. Please use --help for help."
             ;;
@@ -681,11 +626,6 @@ cmd_shell() {
     ensure_devctr
     ensure_build_dir
 
-    if [[ $ramdisk = true ]]; then
-        mount_ramdisk ${ramdisk_size}
-        ramdisk_args="--volume ${DEFAULT_RAMDISK_PATH}:${DEFAULT_TEST_SESSION_ROOT_PATH}"
-    fi
-
     if [[ $privileged = true ]]; then
         # If requested, spin up a privileged container.
         #
@@ -699,8 +639,6 @@ cmd_shell() {
             --ulimit memlock=-1:-1 \
             --security-opt seccomp=unconfined \
             --workdir "$CTR_FC_ROOT_DIR" \
-            -v /boot:/boot \
-            ${ramdisk_args} \
             -- \
             bash
         ret=$?
@@ -732,10 +670,6 @@ cmd_shell() {
         ret=$?
     fi
 
-    if [[ $ramdisk = true ]]; then
-        umount_ramdisk
-    fi
-
     return $ret
 }