do not complain if attempt to resizefs in an lxc container fails

it is expected / understood that mknod would fail inside an lxc container.
So, if thats the case, just log a debug message saying so.

LP: #800856

2 files changed, 26 insertions, 0 deletions

diff --git a/cloudinit/CloudConfig/cc_resizefs.py b/cloudinit/CloudConfig/cc_resizefs.py
index e396b283..883c269b 100644
--- a/cloudinit/CloudConfig/cc_resizefs.py
+++ b/cloudinit/CloudConfig/cc_resizefs.py
@@ -42,6 +42,9 @@ def handle(name,cfg,cloud,log,args):
        dev=os.makedev(os.major(st_dev),os.minor(st_dev))
        os.mknod(devpth, 0400 | stat.S_IFBLK, dev)
     except:
+        if util.islxc():
+            log.debug("inside lxc, ignoring mknod failure in resizefs")
+            return
         log.warn("Failed to make device node to resize /")
         raise
 
diff --git a/cloudinit/util.py b/cloudinit/util.py
index 8f6a6b0d..ec37f2f7 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -395,3 +395,26 @@ def dos2unix(input):
     pos = input.find('\n')
     if pos <= 0 or input[pos-1] != '\r': return(input)
     return(input.replace('\r\n','\n'))
+
+def islxc():
+    # is this host running lxc?
+    try:
+        with open("/proc/1/cgroup") as f:
+            if f.read() == "/": 
+                return True
+    except IOError as e:
+        if e.errno != errno.ENOENT:
+            raise
+
+    try:
+        # try to run a program named 'lxc-is-container'. if it returns true, then
+        # we're inside a container. otherwise, no
+        sp = subprocess.Popen(['lxc-is-container'], stdout=subprocess.PIPE,
+                              stderr=subprocess.PIPE)
+        out,err = sp.communicate(None)
+        return(sp.returncode == 0)
+    except OSError as e:
+        if e.errno != errno.ENOENT:
+            raise
+
+    return False