8567: Rename docker19-migrate to migrate-docker19 for consistency with

[arvados.git] / docker / migrate-docker19 / dnd.sh

diff --git a/docker/migrate-docker19/dnd.sh b/docker/migrate-docker19/dnd.sh
new file mode 100755 (executable)
index 0000000..ce72601
--- /dev/null
+++ b/docker/migrate-docker19/dnd.sh
@@ -0,0 +1,101 @@
+#!/bin/bash
+
+# Taken from https://github.com/jpetazzo/dind
+
+exec 2>&1
+
+# Ensure that all nodes in /dev/mapper correspond to mapped devices currently loaded by the device-mapper kernel driver
+dmsetup mknodes
+
+: {LOG:=stdio}
+
+# First, make sure that cgroups are mounted correctly.
+CGROUP=/sys/fs/cgroup
+[ -d $CGROUP ] || mkdir $CGROUP
+
+if mountpoint -q $CGROUP ; then
+    break
+else
+    mount -n -t tmpfs -o uid=0,gid=0,mode=0755 cgroup $CGROUP
+fi
+
+if ! mountpoint -q $CGROUP ; then
+    echo "Could not find or mount cgroups. Tried /sys/fs/cgroup and /cgroup.  Did you use --privileged?"
+    exit 1
+fi
+
+if [ -d /sys/kernel/security ] && ! mountpoint -q /sys/kernel/security
+then
+    mount -t securityfs none /sys/kernel/security || {
+        echo "Could not mount /sys/kernel/security."
+        echo "AppArmor detection and --privileged mode might break."
+    }
+fi
+
+# Mount the cgroup hierarchies exactly as they are in the parent system.
+for SUBSYS in $(cut -d: -f2 /proc/1/cgroup)
+do
+        [ -d $CGROUP/$SUBSYS ] || mkdir $CGROUP/$SUBSYS
+        mountpoint -q $CGROUP/$SUBSYS ||
+                mount -n -t cgroup -o $SUBSYS cgroup $CGROUP/$SUBSYS
+
+        # The two following sections address a bug which manifests itself
+        # by a cryptic "lxc-start: no ns_cgroup option specified" when
+        # trying to start containers withina container.
+        # The bug seems to appear when the cgroup hierarchies are not
+        # mounted on the exact same directories in the host, and in the
+        # container.
+
+        # Named, control-less cgroups are mounted with "-o name=foo"
+        # (and appear as such under /proc/<pid>/cgroup) but are usually
+        # mounted on a directory named "foo" (without the "name=" prefix).
+        # Systemd and OpenRC (and possibly others) both create such a
+        # cgroup. To avoid the aforementioned bug, we symlink "foo" to
+        # "name=foo". This shouldn't have any adverse effect.
+        echo $SUBSYS | grep -q ^name= && {
+                NAME=$(echo $SUBSYS | sed s/^name=//)
+                ln -s $SUBSYS $CGROUP/$NAME
+        }
+
+        # Likewise, on at least one system, it has been reported that
+        # systemd would mount the CPU and CPU accounting controllers
+        # (respectively "cpu" and "cpuacct") with "-o cpuacct,cpu"
+        # but on a directory called "cpu,cpuacct" (note the inversion
+        # in the order of the groups). This tries to work around it.
+        [ $SUBSYS = cpuacct,cpu ] && ln -s $SUBSYS $CGROUP/cpu,cpuacct
+done
+
+# Note: as I write those lines, the LXC userland tools cannot setup
+# a "sub-container" properly if the "devices" cgroup is not in its
+# own hierarchy. Let's detect this and issue a warning.
+grep -q :devices: /proc/1/cgroup ||
+       echo "WARNING: the 'devices' cgroup should be in its own hierarchy."
+grep -qw devices /proc/1/cgroup ||
+       echo "WARNING: it looks like the 'devices' cgroup is not mounted."
+
+# Now, close extraneous file descriptors.
+pushd /proc/self/fd >/dev/null
+for FD in *
+do
+       case "$FD" in
+       # Keep stdin/stdout/stderr
+       [012])
+               ;;
+       # Nuke everything else
+       *)
+               eval exec "$FD>&-"
+               ;;
+       esac
+done
+popd >/dev/null
+
+
+# If a pidfile is still around (for example after a container restart),
+# delete it so that docker can start.
+rm -rf /var/run/docker.pid
+
+read pid cmd state ppid pgrp session tty_nr tpgid rest < /proc/self/stat
+
+if ! docker daemon --storage-driver=overlay $DOCKER_DAEMON_ARGS ; then
+    docker daemon $DOCKER_DAEMON_ARGS
+fi