[PATCHES] CTDB: improved IPv6 support

Stefan (metze) Metzmacher metze at samba.org
Fri Dec 5 06:42:40 MST 2014

Am 05.12.2014 um 14:39 schrieb Amitay Isaacs:
> Hi Martin,
> On Thu, Dec 4, 2014 at 11:27 PM, Martin Schwenke <martin at meltin.net> wrote:
>> On Thu, 4 Dec 2014 17:42:51 +1100, Martin Schwenke <martin at meltin.net>
>> wrote:
>>> The attached patch series fixes most problems with IPv6 in CTDB.
>>> The most notable things are:
>>> * For machine-readable output from the "ctdb" CLI tool, effectively
>>>   replace "ctdb -Y ..." with "ctdb -X ..." which uses '|' as the field
>>>   delimiter.  For those that don't want '|', they can use
>>>   "ctdb -x<char> ...".
>>>   "ctdb -Y ..." is still supported but all documentation and scripts
>>>   now use "ctdb -X".
>>>   Mathieu, you're CC:ed because this includes a minor change to the
>>>   nagios script, which I think is correct but it isn't yet tested. :-)
>>> * When the CTDB daemon loads the nodes file it stores a string
>>>   representation of each node's IP address.  This representation is now
>>>   first converted to canonical form so that IPv6 addresses will
>>>   compare more reliably.
>>> * Some functionality has moved from the daemon to the 10.interfaces
>>>   eventscript and it now works with IPv6 addresses.
>>>   For the past couple of years the release IP code in the daemon has
>>>   depended on being able to determine which interface an IP address is
>>>   on, rather than trusting vnn->interface.  This was done to more
>>>   reliably be able to remove rogue IP addresses (present due to
>>>   either race conditions or addresses that have been moved by hand).
>>>   This is not as easy for IPv6 addresses since the SIOCGIFCONF ioctl
>>>   does not support IPv6.
>>>   Therefore, this code has been removed and vnn->interface is now
>>>   passed to the "releaseip" event, even when it is NULL (in which case
>>>   "__none__" is passed).  In all cases the eventscript now uses some "ip
>>>   addr show to ..." magic to determine the actual interface and netmask
>>>   for an IP address being released.  If either of these differ from
>>>   what was passed then a warning is logged, and the actual interface
>>>   and netmask are used to delete the IP address.
>>>   I don't think we lost any functionality.  The main part of this is in
>>>   these patches:
>>>     32c2eab ctdb-scripts: Make 10.interface IPv6-safe
>>>     837f36a ctdb-daemon: Trust vnn->interface for an IP when releasing it
>>> * Gratuitous ARP equivalent for IPv6 has been changed to use neighbor
>>>   advertisements.  This seems to work reliably.
>>> * Due to duplicate address detection in IPv6, the IP address addition
>>>   code will try to wait until IPv6 addresses are no longer
>>>   "tentative".  If this times out or "dadfail" occurs then the IP
>>>   address is removed and the operation fails.  Note that this could
>>>   cause an outage (all nodes unhealthy, one at a time) if a rogue node
>>>   refuses to release IPs or if CTDB just dies.  It isn't possible to
>>>   easily work around this, so it is a design limitation and may need to
>>>   be looked at again in the future.
>>> This has been tested on a virtual cluster with IPv6 addresses only, on
>>> both public and private networks.
>>> Please review and push if OK.
>>> These patches are in my ctdb-ipv6 branch:
>> http://git.samba.org/?p=martins/samba.git;a=shortlog;h=refs/heads/ctdb-ipv6
>>> Still to do:
>>> * Update policy routing to work with IPv6.  There's some code in there
>>>   that only works for IPv4.
>>> * Other features like LVS.
>> Darn.  This looks like it was big enough to be moderated, so...
>> These patches:
>> b615d09f ctdb-tools: Produce machine readable output with new function
>> printm()
>> fdf0461 ctdb-tools: Add -x option to specify delimiter for machine
>> readable output
>> 42498ee ctdb-tools: Add -X option for machine parsable output with
>> separator '|'
>> 8485235 ctdb-scripts: Update eventscripts to use ctdb -X instead of ctdb -Y
>> 435c200 ctdb-tools: Update onnode and ctdb-diagnostics to use ctdb -X
>> 8f1ebc5 ctdb-tests: Update integration tests to use ctdb -X
>> 443aa32 ctdb-tool: Fix "ctdb -Y ifaces" output to have trailing delimiters
>> c2e39e4 ctdb-doc: Update examples to use ctdb -X
>> 1ea9d2e ctdb-utils: Update Nagios code to use ctdb -X
>> c6a448c ctdb-scripts: Add IPv6 addresses support in ip_maskbits_iface()
>> 9e6d323 ctdb-scripts: New functions ip6tables() and iptables_wrapper()
>> 32c2eab ctdb-scripts: Make 10.interface IPv6-safe
>> 837f36a ctdb-daemon: Trust vnn->interface for an IP when releasing it
>> b7debd7 ctdb-eventscripts: Specify broadcast optionally to ip addr add
>> 38a5617 ctdb-scripts: Wait until IPv6 addresses are not "tentative"
>> 7944a40 ctdb-daemon: Fix IP address comparisons for IPv6 addresses
>> 51ec7d3 ctdb-tools: Bracket IP addresses in onnode (for IPv6)
>> 9d4137d ctdb-tests: Extend regexp to match IPv6 addresses
>> c9f3359 ctdb-tests: Try to handle IPv6 addresses for local daemons
> In this patch, we cannot change the node IP addresses from 127.0.0.x to
> 127.0.234.x.  Looks like socket wrapper does not like that, socket wrapper
> expects addresses in range.  So here's a fixup to move node
> IPs away from
> diff --git a/ctdb/tests/simple/scripts/local_daemons.bash
> b/ctdb/tests/simple/scripts/local_daemons.bash
> index 0131950..7d35a8f 100644
> --- a/ctdb/tests/simple/scripts/local_daemons.bash
> +++ b/ctdb/tests/simple/scripts/local_daemons.bash
> @@ -76,7 +76,8 @@ setup_ctdb ()
>                 echo "fc00:10::1:$(($i + $TEST_LOCAL_DAEMONS))/64 lo"
>>> "$public_addresses_all"
>             fi
>         else
> -           echo 127.0.234.$i >>"$CTDB_NODES"
> +           j=$(( $i + 10))
> +           echo 127.0.0.$j >>"$CTDB_NODES"
>             # 2 public addresses on most nodes, just to make things
> interesting.
>             if [ $(($i - 1)) -ne $no_public_ips ] ; then
>                 echo "192.168.234.$i/24 lo" >>"$public_addresses_all"

Maybe also the ipv6 socket_wrapper range:

Samba uses this:

$ctx->{ipv6} = sprintf("fd00:0000:0000:0000:0000:0000:5357:5f%02x",


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