On the host when we start a container, it will be placed in a cgroup path of /machine.slice/machine-lxc\x2ddemo.scope under /sys/fs/cgroup/* Inside the containers' namespace we need to setup /sys/fs/cgroup mounts, and currently will bind mount /machine.slice/machine-lxc\x2ddemo.scope on the host to appear as / in the container. While this may sound nice, it confuses applications dealing with cgroups, because /proc/$PID/cgroup now does not match the directory in /sys/fs/cgroup This particularly causes problems for systems and will make it create repeated path components in the cgroup for apps run in the container eg /machine.slice/machine-lxc\x2ddemo.scope/machine.slice/machine-lxc\x2ddemo.scope/user.slice/user-0.slice/session-61.scope This also causes any systemd service that uses sd-notify to fail to start, because when systemd receives the notification it won't be able to identify the corresponding unit it came from. In particular this break rabbitmq-server startup Future kernels will provide proper cgroup namespacing which will handle this problem, but until that time we should not try to play games with hiding parent cgroups. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- src/libvirt_private.syms | 2 +- src/lxc/lxc_container.c | 2 +- src/util/vircgroup.c | 9 ++++----- src/util/vircgroup.h | 6 +++--- 4 files changed, 9 insertions(+), 10 deletions(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 5e05a98..1732421 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1194,6 +1194,7 @@ virCgroupAllowDevice; virCgroupAllowDeviceMajor; virCgroupAllowDevicePath; virCgroupAvailable; +virCgroupBindMount; virCgroupControllerAvailable; virCgroupControllerTypeFromString; virCgroupControllerTypeToString; @@ -1231,7 +1232,6 @@ virCgroupGetMemSwapUsage; virCgroupGetPercpuStats; virCgroupHasController; virCgroupHasEmptyTasks; -virCgroupIsolateMount; virCgroupKill; virCgroupKillPainfully; virCgroupKillRecursive; diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index c5a70a1..a6805ac 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -1827,7 +1827,7 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, /* Now we can re-mount the cgroups controllers in the * same configuration as before */ - if (virCgroupIsolateMount(cgroup, "/.oldroot/", sec_mount_options) < 0) + if (virCgroupBindMount(cgroup, "/.oldroot/", sec_mount_options) < 0) goto cleanup; /* Mounts /dev */ diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c index 7584ee4..d7f4065 100644 --- a/src/util/vircgroup.c +++ b/src/util/vircgroup.c @@ -3917,8 +3917,8 @@ virCgroupGetFreezerState(virCgroupPtr group, char **state) int -virCgroupIsolateMount(virCgroupPtr group, const char *oldroot, - const char *mountopts) +virCgroupBindMount(virCgroupPtr group, const char *oldroot, + const char *mountopts) { int ret = -1; size_t i; @@ -3954,10 +3954,9 @@ virCgroupIsolateMount(virCgroupPtr group, const char *oldroot, if (!virFileExists(group->controllers[i].mountPoint)) { char *src; - if (virAsprintf(&src, "%s%s%s", + if (virAsprintf(&src, "%s%s", oldroot, - group->controllers[i].mountPoint, - group->controllers[i].placement) < 0) + group->controllers[i].mountPoint) < 0) goto cleanup; VIR_DEBUG("Create mount point '%s'", diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h index 63a9e1c..d754b1f 100644 --- a/src/util/vircgroup.h +++ b/src/util/vircgroup.h @@ -286,9 +286,9 @@ int virCgroupKill(virCgroupPtr group, int signum); int virCgroupKillRecursive(virCgroupPtr group, int signum); int virCgroupKillPainfully(virCgroupPtr group); -int virCgroupIsolateMount(virCgroupPtr group, - const char *oldroot, - const char *mountopts); +int virCgroupBindMount(virCgroupPtr group, + const char *oldroot, + const char *mountopts); bool virCgroupSupportsCpuBW(virCgroupPtr cgroup); -- 2.5.0