[PATCH iproute2 v3] man ip-netns: Notice about loose device when do 'del'

[PATCH iproute2 v3] man ip-netns: Notice about loose device when do 'del'

[Vadim Kochan]

From: Vadim Kochan <vadim4j@gmail.com>

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
---
v3:
    Fixed typos - noticed by Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
v2:
    Fixed wrong 'xargs' command - noticed by Christoph Schulz <develop@kristov.de>

 man/man8/ip-netns.8 | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/man/man8/ip-netns.8 b/man/man8/ip-netns.8
index 28a9544..d496675 100644
--- a/man/man8/ip-netns.8
+++ b/man/man8/ip-netns.8
@@ -46,6 +46,9 @@ ip-netns \- process network namespace management
 A network namespace is logically another copy of the network stack,
 with its own routes, firewall rules, and network devices.
 
+By default process inherits network namespace from its parent. Initially all
+the processes share the same default network namespace from the init process.
+
 By convention a named network namespace is an object at
 .BR "/var/run/netns/" NAME
 that can be opened.  The file descriptor resulting from opening
@@ -88,14 +91,30 @@ network namespace and assigns NAME.
 .sp
 If NAME is present in /var/run/netns it is umounted and the mount
 point is removed.  If this is the last user of the network namespace the
-network namespace will be freed, otherwise the network namespace
-persists until it has no more users.  ip netns delete may fail if
-the mount point is in use in another mount namespace.
+network namespace will be freed and all physical devices will be moved to the
+default one, otherwise the network namespace persists until it has no more
+users. ip netns delete may fail if the mount point is in use in another mount
+namespace.
 
 If
 .B -all
 option was specified then all the network namespace names will be removed.
 
+It is possible to lose the physical device when it was moved to netns and
+then this netns was deleted with a running process:
+
+    $ ip netns add net0
+    $ ip link set dev eth0 netns net0
+    $ ip netns exec net0 SOME_PROCESS_IN_BACKGROUND
+    $ ip netns del net0
+
+and eth0 will appear in the default netns only after SOME_PROCESS_IN_BACKGROUND
+will exit or will be killed. To prevent this the processes running in net0
+should be killed before deleting the netns:
+
+    $ ip netns pids net0 | xargs kill
+    $ ip netns del net0
+
 .TP
 .B ip netns set NAME NETNSID - assign an id to a peer network namespace
 .sp
-- 
2.3.1

Re: [PATCH iproute2 v3] man ip-netns: Notice about loose device when do 'del'

[Ben Hutchings]

[-- Attachment #1: Type: text/plain, Size: 905 bytes --]

On Sun, 2015-03-15 at 17:49 +0200, Vadim Kochan wrote:
[...]
> --- a/man/man8/ip-netns.8
> +++ b/man/man8/ip-netns.8
> @@ -46,6 +46,9 @@ ip-netns \- process network namespace management
>  A network namespace is logically another copy of the network stack,
>  with its own routes, firewall rules, and network devices.
>  
> +By default process inherits network namespace from its parent. Initially all

Missing "a" before "process".

[...]
> +It is possible to lose the physical device when it was moved to netns and
> +then this netns was deleted with a running process:
> +
> +    $ ip netns add net0
> +    $ ip link set dev eth0 netns net0
> +    $ ip netns exec net0 SOME_PROCESS_IN_BACKGROUND
> +    $ ip netns del net0
[...]

Use the .RS and .RE macros to begin and end indented text, not spaces.

Ben.

-- 
Ben Hutchings
All extremists should be taken out and shot.


[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 811 bytes --]