checkpoint: support lazy migration

tests/integration/checkpoint.bats

@@ -122,3 +122,111 @@ function teardown() {
   [ "$status" -eq 0 ]
   [[ "${output}" == *"ponG Ping"* ]]
 }
+
+@test "checkpoint --lazy-pages and restore" {
+  # XXX: currently criu require root containers.
+  requires criu root
+
+  # check if lazy-pages is supported
+  run ${CRIU} check --feature lazy_pages
+  if [ "$status" -eq 1 ]; then
+    # this criu does not support lazy migration; skip the test
+    skip "this criu does not support lazy migration"
+  fi
+
+  sed -i 's;"terminal": true;"terminal": false;' config.json
+  sed -i 's;"readonly": true;"readonly": false;' config.json
+  sed -i 's/"sh"/"sh","-c","for i in `seq 10`; do read xxx || continue; echo ponG $xxx; done"/' config.json
+
+  # The following code creates pipes for stdin and stdout.
+  # CRIU can't handle fifo-s, so we need all these tricks.
+  fifo=`mktemp -u /tmp/runc-fifo-XXXXXX`
+  mkfifo $fifo
+
+  # For lazy migration we need to know when CRIU is ready to serve
+  # the memory pages via TCP.
+  lazy_pipe=`mktemp -u /tmp/lazy-pipe-XXXXXX`
+  mkfifo $lazy_pipe
+
+  # TCP port for lazy migration
+  port=27277
+
+  # stdout
+  cat $fifo | cat $fifo &
+  pid=$!
+  exec 50</proc/$pid/fd/0
+  exec 51>/proc/$pid/fd/0
+
+  # stdin
+  cat $fifo | cat $fifo &
+  pid=$!
+  exec 60</proc/$pid/fd/0
+  exec 61>/proc/$pid/fd/0
+
+  echo -n > $fifo
+  unlink $fifo
+
+  # run busybox
+  __runc run -d test_busybox <&60 >&51 2>&51
+  [ $? -eq 0 ]
+
+  testcontainer test_busybox running
+
+  # checkpoint the running container
+  mkdir image-dir
+  mkdir work-dir
+  # Double fork taken from helpers.bats
+  # We need to start 'runc checkpoint --lazy-pages' in the background,
+  # so we double fork in the shell.
+  (runc --criu "$CRIU" checkpoint --lazy-pages --page-server 0.0.0.0:${port} --status-fd ${lazy_pipe} --work-path ./work-dir --image-path ./image-dir test_busybox & ) &
+  # Sleeping here. This is ugly, but not sure how else to handle it.
+  # The return code of the in the background running runc is needed, if
+  # there is some basic error. If the lazy migration is ready can
+  # be handled by $lazy_pipe. Which probably will always be ready
+  # after sleeping two seconds.
+  sleep 2
+  # Check if inventory.img was written
+  [ -e image-dir/inventory.img ]
+  # If the inventory.img exists criu checkpointed some things, let's see
+  # if there were other errors in the log file.
+  run grep -B 5 Error ./work-dir/dump.log -q
+  [ "$status" -eq 1 ]
+
+  # This will block until CRIU is ready to serve memory pages
+  cat $lazy_pipe
+  [ "$status" -eq 1 ]
+
+  unlink $lazy_pipe
+
+  # Double fork taken from helpers.bats
+  # We need to start 'criu lazy-pages' in the background,
+  # so we double fork in the shell.
+  # Start CRIU in lazy-daemon mode
+  $(${CRIU} lazy-pages --page-server --address 127.0.0.1 --port ${port} -D image-dir &) &
+
+  # Restore lazily from checkpoint.
+  # The restored container needs a different name as the checkpointed
+  # container is not yet destroyed. It is only destroyed at that point
+  # in time when the last page is lazily transferred to the destination.
+  # Killing the CRIU on the checkpoint side will let the container
+  # continue to run if the migration failed at some point.
+  __runc --criu "$CRIU" restore -d --work-path ./image-dir --image-path ./image-dir --lazy-pages test_busybox_restore <&60 >&51 2>&51
+  ret=$?
+  [ $ret -eq 0 ]
+  run grep -B 5 Error ./work-dir/dump.log -q
+  [ "$status" -eq 1 ]
+
+  # busybox should be back up and running
+  testcontainer test_busybox_restore running
+
+  runc exec --cwd /bin test_busybox_restore echo ok
+  [ "$status" -eq 0 ]
+  [[ ${output} == "ok" ]]
+
+  echo Ping >&61
+  exec 61>&-
+  exec 51>&-
+  run cat <&50
+  [ "$status" -eq 0 ]
+  [[ "${output}" == *"ponG Ping"* ]]
+}