[lxc-devel] [PATCH] lxc-ls: Implement support for nested containers
Stéphane Graber
stgraber at ubuntu.com
Thu Feb 28 23:40:12 UTC 2013
Add initial support for showing and querying nested containers.
This is done through a new --nesting argument to lxc-ls and uses
lxc-attach to go look for sub-containers.
Known limitations include the dependency on setns support for the PID
and NETWORK namespaces and the assumption that LXCPATH for the sub-containers
matches that of the host.
Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
---
doc/lxc-ls.sgml.in | 12 +++++++
src/lxc/lxc-ls | 75 ++++++++++++++++++++++++++++++++++-----
src/python-lxc/lxc/__init__.py.in | 15 ++------
3 files changed, 81 insertions(+), 21 deletions(-)
diff --git a/doc/lxc-ls.sgml.in b/doc/lxc-ls.sgml.in
index 83618e5..877404d 100644
--- a/doc/lxc-ls.sgml.in
+++ b/doc/lxc-ls.sgml.in
@@ -56,6 +56,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<arg choice="opt">--stopped</arg>
<arg choice="opt">--fancy</arg>
<arg choice="opt">--fancy-format</arg>
+ <arg choice="opt">--nesting</arg>
<arg choice="opt">filter</arg>
</cmdsynopsis>
</refsynopsisdiv>
@@ -152,6 +153,17 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<varlistentry>
<term>
+ <option><optional>--nesting</optional></option>
+ </term>
+ <listitem>
+ <para>
+ Show nested containers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
<option><optional>filter</optional></option>
</term>
<listitem>
diff --git a/src/lxc/lxc-ls b/src/lxc/lxc-ls
index 92a4e53..6468890 100644
--- a/src/lxc/lxc-ls
+++ b/src/lxc/lxc-ls
@@ -31,9 +31,11 @@ warnings.filterwarnings("ignore", "The python-lxc API isn't yet stable")
import argparse
import gettext
+import json
import lxc
import os
import re
+import subprocess
import sys
_ = gettext.gettext
@@ -85,6 +87,23 @@ def getTerminalSize():
return int(cr[1]), int(cr[0])
+
+def getSubContainers(container, lxcpath):
+ attach = ['lxc-attach', '-R', '-s', 'NETWORK|PID', '-n', container,
+ '--', sys.argv[0], "--nesting"]
+
+ with open(os.devnull, "w") as fd:
+ newenv = dict(os.environ)
+ newenv['NESTED'] = "/proc/1/root/%s" % lxcpath
+ sp = subprocess.Popen(attach, stderr=fd, stdout=subprocess.PIPE,
+ env=newenv, universal_newlines=True)
+ sp.wait()
+ out = sp.stdout.read()
+ if out:
+ return json.loads(out)
+ return None
+
+
# Begin parsing the command line
parser = argparse.ArgumentParser(description=_("LXC: List containers"),
formatter_class=argparse.RawTextHelpFormatter)
@@ -93,7 +112,8 @@ parser.add_argument("-1", dest="one", action="store_true",
help=_("list one container per line (default when piped)"))
parser.add_argument("-P", "--lxcpath", dest="lxcpath", metavar="PATH",
- help=_("Use specified container path"), default=None)
+ help=_("Use specified container path"),
+ default=lxc.default_config_path)
parser.add_argument("--active", action="store_true",
help=_("list only active containers "
@@ -114,6 +134,9 @@ parser.add_argument("--fancy", action="store_true",
parser.add_argument("--fancy-format", type=str, default="name,state,ipv4,ipv6",
help=_("comma separated list of fields to show"))
+parser.add_argument("--nesting", dest="nesting", action="store_true",
+ help=_("show nested containers"))
+
parser.add_argument("filter", metavar='FILTER', type=str, nargs="?",
help=_("regexp to be applied on the container list"))
@@ -129,6 +152,9 @@ if args.active:
if not sys.stdout.isatty():
args.one = True
+# Set the lookup path for the containers
+lxcpath = os.environ.get('NESTED', args.lxcpath)
+
# Turn args.fancy_format into a list
args.fancy_format = args.fancy_format.strip().split(",")
@@ -141,7 +167,7 @@ if not os.geteuid() == 0 and (args.fancy or args.state):
# List of containers, stored as dictionaries
containers = []
-for container_name in lxc.list_containers(config_path=args.lxcpath):
+for container_name in lxc.list_containers(config_path=lxcpath):
entry = {}
entry['name'] = container_name
@@ -150,7 +176,7 @@ for container_name in lxc.list_containers(config_path=args.lxcpath):
continue
# Return before grabbing the object (non-root)
- if not args.state and not args.fancy:
+ if not args.state and not args.fancy and not args.nesting:
containers.append(entry)
continue
@@ -161,28 +187,47 @@ for container_name in lxc.list_containers(config_path=args.lxcpath):
continue
# Nothing more is needed if we're not printing some fancy output
- if not args.fancy:
+ if not args.fancy and not args.nesting:
containers.append(entry)
continue
# Some extra field we may want
- if 'state' in args.fancy_format:
+ if 'state' in args.fancy_format or args.nesting:
entry['state'] = container.state
- if 'pid' in args.fancy_format:
+
+ if 'pid' in args.fancy_format or args.nesting:
entry['pid'] = "-"
if container.init_pid != -1:
entry['pid'] = str(container.init_pid)
# Get the IPs
for protocol in ('ipv4', 'ipv6'):
- if protocol in args.fancy_format:
+ if protocol in args.fancy_format or args.nesting:
entry[protocol] = "-"
ips = container.get_ips(protocol=protocol, timeout=1)
if ips:
entry[protocol] = ", ".join(ips)
+ # Append the container
containers.append(entry)
+ # Nested containers
+ if args.nesting:
+ sub = getSubContainers(container_name, args.lxcpath)
+ if sub:
+ for entry in sub:
+ if 'nesting_parent' not in entry:
+ entry['nesting_parent'] = []
+ entry['nesting_parent'].insert(0, container_name)
+ entry['nesting_real_name'] = entry.get('nesting_real_name',
+ entry['name'])
+ entry['name'] = "%s -> %s" % (container_name, entry['name'])
+ containers += sub
+
+# Deal with json output:
+if 'NESTED' in os.environ:
+ print(json.dumps(containers))
+ sys.exit(0)
# Print the list
## Standard list with one entry per line
@@ -226,7 +271,12 @@ if args.fancy:
for container in containers:
for field in args.fancy_format:
- if len(container[field]) > field_maxlength[field]:
+ if field == 'name' and 'nesting_real_name' in container:
+ fieldlen = len(" " * ((len(container['nesting_parent']) - 1)
+ * 4) + " \_ " + container['nesting_real_name'])
+ if fieldlen > field_maxlength[field]:
+ field_maxlength[field] = fieldlen
+ elif len(container[field]) > field_maxlength[field]:
field_maxlength[field] = len(container[field])
# Generate the line format string based on the maximum length and
@@ -250,5 +300,12 @@ if args.fancy:
# Print the entries
for container in sorted(containers,
key=lambda container: container['name']):
- fields = [container[field] for field in args.fancy_format]
+ fields = []
+ for field in args.fancy_format:
+ if field == 'name' and 'nesting_real_name' in container:
+ prefix = " " * ((len(container['nesting_parent']) - 1) * 4)
+ fields.append(prefix + " \_ " + container['nesting_real_name'])
+ else:
+ fields.append(container[field])
+
print(line_format.format(fields=fields))
diff --git a/src/python-lxc/lxc/__init__.py.in b/src/python-lxc/lxc/__init__.py.in
index e262c23..f1848f2 100644
--- a/src/python-lxc/lxc/__init__.py.in
+++ b/src/python-lxc/lxc/__init__.py.in
@@ -337,18 +337,9 @@ class Container(_lxc.Container):
Returns the list of IP addresses for the container.
"""
- if not self.defined or not self.running:
+ if not self.running:
return False
- try:
- os.makedirs("/run/netns")
- except:
- pass
-
- path = tempfile.mktemp(dir="/run/netns")
-
- os.symlink("/proc/%s/ns/net" % self.init_pid, path)
-
ips = []
count = 0
@@ -356,7 +347,8 @@ class Container(_lxc.Container):
if count != 0:
time.sleep(1)
- base_cmd = ["ip", "netns", "exec", path.split("/")[-1], "ip"]
+ base_cmd = ["lxc-attach", "-s", "NETWORK", "-n", self.name, "--",
+ "ip"]
# Get IPv6
if protocol in ("ipv6", None):
@@ -397,7 +389,6 @@ class Container(_lxc.Container):
count += 1
- os.remove(path)
return ips
def get_keys(self, key=None):
--
1.8.1.2
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