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Re: [Samba] ctdb vacuum timeouts and record locks




hm, I stand correct on the problem solved statement below. Ip addresses are simply not cooperating on the 2nd node.

root@vault1:~# ctdb ip
Public IPs on node 0
192.168.120.90 0
192.168.120.91 0
192.168.120.92 0
192.168.120.93 0

root@vault2:/service/ctdb/log/main# ctdb ip
Public IPs on node 1
192.168.120.90 0
192.168.120.91 0
192.168.120.92 0
192.168.120.93 0

root@vault2:/service/ctdb/log/main# ctdb moveip 192.168.120.90 1
Control TAKEOVER_IP failed, ret=-1
Failed to takeover IP on node 1

root@vault1:~# ctdb moveip 192.168.120.90 0
Memory allocation error

root@vault2:/service/ctdb/log/main# ctdb ipinfo 192.168.120.90
Public IP[192.168.120.90] info on node 1
IP:192.168.120.90
CurrentNode:0
NumInterfaces:1
Interface[1]: Name:eth0 Link:up References:0

Logs on vault2 (stays banned because it can't obtain IP):
IP 192.168.120.90 still hosted during release IP callback, failing
IP 192.168.120.92 still hosted during release IP callback, failing

root@vault1:~# ctdb delip 192.168.120.90
root@vault1:~# ctdb delip 192.168.120.92
root@vault2:/service/ctdb/log/main# ctdb addip 192.168.120.90/22 eth0
Node already knows about IP 192.168.120.90
root@vault2:/service/ctdb/log/main# ctdb ip
Public IPs on node 1
192.168.120.90 -1
192.168.120.91 0
192.168.120.92 -1
192.168.120.93 0


I am using the 10.external. ip addr show shows the correct IP addresses on eth0 in the lxc container. rebooted the physical machine, this node is buggered. shut it down, used ip addr add to put the addresses on the other node, used ctdb addip and the node took it and node1 is now functioning with all 4 IPs just fine. Or so it appears right now.

something is seriously schizophrenic here...




On 2017-11-02 11:17 AM, Computerisms Corporation via samba wrote:
Hi,

This occurred again this morning, when the user reported the problem, I found in the ctdb logs that vacuuming has been going on since last night.  The need to fix it was urgent (when isn't it?) so I didn't have time to poke around for clues, but immediately restarted the lxc container.  But this time it wouldn't restart, which I had time to trace to a hung smbd process, and between that and a run of the debug_locks.sh script, I traced it to the user reporting the problem.  Given that the user was primarily having problems with files in a given folder, I am thinking this is because of some kind of lock on a file within that folder.

Ended up rebooting both physical machines, problem solved.  for now.

So, not sure how to determine if this is a gluster problem, an lxc problem, or a ctdb/smbd problem.  Thoughts/suggestions are welcome...

On 2017-10-27 10:09 AM, Computerisms Corporation via samba wrote:
Hi Martin,

Thanks for reading and taking the time to reply

ctdbd[89]: Unable to get RECORD lock on database locking.tdb for 20 seconds
/usr/local/samba/etc/ctdb/debug_locks.sh: 142:
/usr/local/samba/etc/ctdb/debug_locks.sh: cannot create : Directory
nonexistent
sh: echo: I/O error
sh: echo: I/O error

That's weird.  The only file really created by that script is the lock
file that is used to make sure we don't debug locks too many times.
That should be in:

   "${CTDB_SCRIPT_VARDIR}/debug_locks.lock"

Next time it happens I will check this.

The other possibility is the use of the script_log() function to try to
get the output logged.  script_log() isn't my greatest moment.  When
debugging you could just replace it with the logger command to get the
output out to syslog.

Okay, that sounds useful, will see what I can do next time I see the problem...

My setup is two servers, the OS is debian and is running samba AD on
dedicated SSDs, and each server has a RAID array of HDDs for storage,
with a mirrored GlusterFS running on top of them.  Each OS has an LXC
container running the clustered member servers with the GlusterFS
mounted to the containers.  The tdb files are in the containers, not on
the shared storage.  I do not use ctdb to start smbd/nmbd.  I can't
think what else is relevant about my setup as it pertains to this issue...

Are the TDB files really on a FUSE filesystem?  Is that an artifact of
the LXC containers?  If so, could it be that locking isn't reliable on
the FUSE filesystem?

No.  The TDB files are in the container, and the container is on the SSD with the OS.  running mount from within the container shows:

/dev/sda1 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)

However, the gluster native client is a fuse-based system, so the data is stored on a fuse system which is mounted in the container:

masterchieflian:ctfngluster on /CTFN type fuse.glusterfs (rw,relatime,user_id=0,group_id=0,allow_other,max_read=131072)

Since this is where the files that become inaccessible are, perhaps this is really where the problem is, and not with the locking.tdb file?  I will investigate about file locks on the gluster system...

Is it possible to try this without the containers?  That would
certainly tell you if the problem is related to the container
infrastructure...

I like to think everything is possible, but it's not really feasible in this case.  Since there are only two physical servers, and they need to be running AD, the only way to separate the containers now is with additional machines to act as member servers.  And because everything tested fine and actually was fine for at least two weeks, these servers are in production now and have been for a few months. If I have to go this way, it will certainly be a last resort...

Thanks again for your reply, will get back to you with what I find...





peace & happiness,
martin




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