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

[PATCH iproute2] 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>
---
 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..062564d 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 inherites network namespace from its parent. Initially all
+the processes shares 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 "loose" 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] man ip-netns: Notice about loose device when do 'del'

[Vadim Kochan]

On Sun, Mar 15, 2015 at 12:47:04PM +0100, Christoph Schulz wrote:
> Hello!
> 
> Vadim Kochan schrieb am Sun, 15 Mar 2015 12:57:24 +0200:
> 
> >[...]
> >+    $ ip netns pids net0 | xargs | kill
> 
> Shouldn't this be rather
> 
>        $ ip netns pids net0 | xargs kill
> 
> ?
> 
> 
> Regards,
> 
> Christoph Schulz
> 

Yes, thank you :-)

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

[Christoph Schulz]

Hello!

Vadim Kochan schrieb am Sun, 15 Mar 2015 12:57:24 +0200:

> [...]
> +    $ ip netns pids net0 | xargs | kill

Shouldn't this be rather

        $ ip netns pids net0 | xargs kill

?


Regards,

Christoph Schulz

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

[Sergei Shtylyov]

Hello.

On 3/15/2015 1:57 PM, Vadim Kochan wrote:

> From: Vadim Kochan <vadim4j@gmail.com>

    Noticed a few typos...

> Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
> ---
>   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..062564d 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 inherites network namespace from its parent. Initially all

    s/inherites/inherits/.

> +the processes shares the same default network namespace from the init process.

    s/shares/share/.

> +
>   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 "loose" the physical device when it was moved to netns and

    Not "lose"?

> +then this netns was deleted with a running process:

[...]

WBR, Sergei

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

[Vadim Kochan]

On Sun, Mar 15, 2015 at 06:20:51PM +0300, Sergei Shtylyov wrote:
> Hello.
> 
> On 3/15/2015 1:57 PM, Vadim Kochan wrote:
> 
> >From: Vadim Kochan <vadim4j@gmail.com>
> 
>    Noticed a few typos...
> 
> >Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
> >---
> >  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..062564d 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 inherites network namespace from its parent. Initially all
> 
>    s/inherites/inherits/.
> 
> >+the processes shares the same default network namespace from the init process.
> 
>    s/shares/share/.
> 
> >+
> >  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 "loose" the physical device when it was moved to netns and
> 
>    Not "lose"?
> 
> >+then this netns was deleted with a running process:
> 
> [...]
> 
> WBR, Sergei
> 

Thank You!