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=== Description (from pull-request) ===
We only do force-premounting if we are on a cgroup2-only system.
While it's paranoid to check for both since cgroup2-only should imply cgroupns
but let's not rely on that.
Closes #6587.
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
From 2a4c2ed0421ec1affb741440eae7a9a5e1f43b0a Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Wed, 11 Dec 2019 16:18:51 +0100
Subject: [PATCH] cgroups: pre-mount on pure-cgroup2 systems with cgroup
namespaces
We only do force-premounting if we are on a cgroup2-only system.
While it's paranoid to check for both since cgroup2-only should imply cgroupns
but let's not rely on that.
Closes #6587.
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
lxd/cgroup/init.go | 23 +++++++++++++++++++++++
lxd/container_lxc.go | 4 +++-
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/lxd/cgroup/init.go b/lxd/cgroup/init.go
index 6cd78e24af..db1ccd734f 100644
--- a/lxd/cgroup/init.go
+++ b/lxd/cgroup/init.go
@@ -6,12 +6,27 @@ import (
"path/filepath"
"strings"
+ "github.com/lxc/lxd/shared"
"github.com/lxc/lxd/shared/logger"
)
+var cgCgroup2SuperMagic int64 = 0x63677270
+
var cgControllers = map[string]Backend{}
+var cgFullCgroup2 bool
+var cgCgroupNamespace bool
func init() {
+ st, err := shared.Statvfs("/sys/fs/cgroup")
+ if err == nil && st.Type == cgCgroup2SuperMagic {
+ cgFullCgroup2 = true
+ }
+
+ _, err = os.Stat("/proc/self/ns/cgroup")
+ if err == nil {
+ cgCgroupNamespace = true
+ }
+
// Go through the list of resource controllers for LXD.
selfCg, err := os.Open("/proc/self/cgroup")
if err != nil {
@@ -72,3 +87,11 @@ func init() {
}
}
}
+
+func WantsMountCgroupsForce() bool {
+ return cgFullCgroup2 && cgCgroupNamespace
+}
+
+func WantsMountCgroupsMixed() bool {
+ return cgCgroupNamespace
+}
diff --git a/lxd/container_lxc.go b/lxd/container_lxc.go
index 2c4e0097ca..972ed44ac4 100644
--- a/lxd/container_lxc.go
+++ b/lxd/container_lxc.go
@@ -781,7 +781,9 @@ func (c *containerLXC) initLXC(config bool) error {
mounts = append(mounts, "sys:rw")
}
- if !shared.PathExists("/proc/self/ns/cgroup") {
+ if cgroup.WantsMountCgroupsForce() {
+ mounts = append(mounts, "cgroup:rw:force")
+ } else if cgroup.WantsMountCgroupsMixed() {
mounts = append(mounts, "cgroup:mixed")
}
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