[PATCHES] CTDB: improved IPv6 support

Martin Schwenke martin at meltin.net
Thu Dec 4 05:27:46 MST 2014

On Thu, 4 Dec 2014 17:42:51 +1100, Martin Schwenke <martin at meltin.net>

> 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
875f60e ctdb-tests: Bracket IP addresses in NFS mounts and scp command (for IPv6)
befdf53 ctdb-tests: Extend regexps to handle IPv6 address matching
b2df1a3 ctdb-tests: Use ping_wrapper to do relevant ping or ping6
1cc75ea0 ctdb-tests: Match IPv6 connections in netstat output
928b88a ctdb-tests: Generalise the gratarp and tickle sniffing code for IPv6
d546cba ctdb-tests: Use ip neigh command instead of arp
07b8aa1 ctdb-tests: Make tcpdump output more verbose
2ed1f6b ctdb-tests: More debug on SSH failure
76e83e5 ctdb-daemon: Gratuitous ARP equivalent for IPv6 is neighbor advertisement
242442a ctdb-tests: Need to drop public IPs in kill-failover tests

from my ctdb-ipv6 branch, per above gitweb link.

As an aside, does someone want to add me as a list moderator?  ;-)

peace & happiness,

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