[ClusterLabs] Issue in fence_ilo4 with IPv6 ILO IPs

Fri Apr 5 07:18:25 EDT 2019

*Further update on this:*
This issue is resolved now. ILO was discarding "Neighbor Advertisement"
(NA) as Solicited flag was set in NA message. Hence it was not updating its
local neighbor table.
As per RFC, Solicited flag should be set only in NA message when it is a
response to Neighbor Solicitation.
After disabling the Solicited flag in NA message, ILO started updating the
local neighbor cache.

On Fri, Apr 5, 2019 at 2:23 PM Rohit Saini <rohitsaini111.forum at gmail.com>
wrote:

> Hi Ondrej,
> Finally found some lead on this.. We started tcpdump on my machine to
> understand the IPMI traffic. Attaching the capture for your reference.
> fd00:1061:37:9021:: is my floating IP and fd00:1061:37:9002:: is my ILO IP.
> When resource movement happens, we are initiating the "Neighbor
> Advertisement" for fd00:1061:37:9021:: (which is on new machine now) so
> that peers can update their neighbor table and starts communication with
> new MAC address.
> Looks like ILO is not updating its neighbor table, as it is still sending
> responding to older MAC.
> After sometime, "Neighbor Solicitation" happens and ILO updates the
> neighbor table. Now this ILO becomes reachable and starts responding
> towards new MAC address.
>
> My ILO firmware is 2.60. We will try again the issue post upgrading my
> firmware.
>
> To verify this theory, after resource movement, I flushed the local
> neighbor table due to which "Neighbor Solicitation" was initiated early and
> this delay in getting ILO response was not seen.
> This fixed the issue.
>
> We are now more interested in understanding why ILO couldnot update its
> neighbor table on receiving "Neighbor Advertisement". FYI, Override flag in
> "Neighbor Advertisement" is already set.
>
> Thanks,
> Rohit
>
> On Thu, Apr 4, 2019 at 8:37 AM Ondrej <ondrej-clusterlabs at famera.cz>
> wrote:
>
>> On 4/3/19 6:10 PM, Rohit Saini wrote:
>> > Hi Ondrej,
>> > Please find my reply below:
>> >
>> > 1.
>> > *Stonith configuration:*
>> > [root at orana ~]# pcs config
>> >   Resource: fence-uc-orana (class=stonith type=fence_ilo4)
>> >    Attributes: delay=0 ipaddr=fd00:1061:37:9002:: lanplus=1 login=xyz
>> > passwd=xyz pcmk_host_list=orana pcmk_reboot_action=off
>> >    Meta Attrs: failure-timeout=3s
>> >    Operations: monitor interval=5s on-fail=ignore
>> > (fence-uc-orana-monitor-interval-5s)
>> >                start interval=0s on-fail=restart
>> > (fence-uc-orana-start-interval-0s)
>> >   Resource: fence-uc-tigana (class=stonith type=fence_ilo4)
>> >    Attributes: delay=10 ipaddr=fd00:1061:37:9001:: lanplus=1 login=xyz
>> > passwd=xyz pcmk_host_list=tigana pcmk_reboot_action=off
>> >    Meta Attrs: failure-timeout=3s
>> >    Operations: monitor interval=5s on-fail=ignore
>> > (fence-uc-tigana-monitor-interval-5s)
>> >                start interval=0s on-fail=restart
>> > (fence-uc-tigana-start-interval-0s)
>> >
>> > Fencing Levels:
>> >
>> > Location Constraints:
>> > Ordering Constraints:
>> >    start fence-uc-orana then promote unicloud-master (kind:Mandatory)
>> >    start fence-uc-tigana then promote unicloud-master (kind:Mandatory)
>> > Colocation Constraints:
>> >    fence-uc-orana with unicloud-master (score:INFINITY)
>> > (rsc-role:Started) (with-rsc-role:Master)
>> >    fence-uc-tigana with unicloud-master (score:INFINITY)
>> > (rsc-role:Started) (with-rsc-role:Master)
>> >
>> >
>> > 2. This is seen randomly. Since I am using colocation, stonith
>> resources
>> > are stopped and started on new master. That time, starting of stonith
>> is
>> > taking variable amount of time.
>> > No other IPv6 issues are seen in the cluster nodes.
>> >
>> > 3. fence_agent version
>> >
>> > [root at orana ~]#  rpm -qa|grep  fence-agents-ipmilan
>> > fence-agents-ipmilan-4.0.11-66.el7.x86_64
>> >
>> >
>> > *NOTE:*
>> > Both IPv4 and IPv6 are configured on my ILO, with "iLO Client
>> > Applications use IPv6 first" turned on.
>> > Attaching corosync logs also.
>> >
>> > Thanks, increasing timeout to 60 worked. But thats not what exactly I
>> am
>> > looking for. I need to know exact reason behind delay of starting these
>> > IPv6 stonith resources.
>> >
>> > Regards,
>> > Rohit
>>
>> Hi Rohit,
>>
>> Thank you for response.
>>
>>  From configuration it is clear that we are using directly IP addresses
>> so the DNS resolution issue can be rules out. There are no messages from
>> fence_ilo4 that would indicate reason why it timed out. So we cannot
>> tell yet what caused the issue. I see that you have enabled
>> PCMK_debug=stonith-ng most probably (or PCMK_debug=yes),
>>
>> It is nice that increased the timeout worked, but as said in previous
>> email it may just mask the real reason why it takes longer to do
>> monitor/start operation.
>>
>>  > Both IPv4 and IPv6 are configured on my ILO, with "iLO Client
>>  > Applications use IPv6 first" turned on.
>> This seems to me to be more related to SNMP communication which we don't
>> use with fence_ilo4 as far as I know. We use the ipmitool on port 623/udp.
>>
>> https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-a00026111en_us&docLocale=en_US#N104B2
>>
>>  > 2. This is seen randomly. Since I am using colocation, stonith
>> resources
>>  > are stopped and started on new master. That time, starting of stonith
>> is
>>  > taking variable amount of time.
>> This is a good observation. Which leads me to question if the iLO has
>> set any kind of session limits for the user that is used here. If there
>> is any session limit it may be worth trying to increase it and test if
>> the same delay can be observed. One situation when this can happen is
>> that when one node communicates with iLO and during that time the
>> communication from other node needs to happen while the limit is 1
>> connection. The relocation of resource from one note to another might
>> fit this, but this is just speculation and fastest way to prove/reject
>> it would be to increase limit, if there is one, and test it.
>>
>> # What more can be done to figure out on what is causing delay?
>>
>> 1. The fence_ilo4 can be configured with attribute 'verbose=1' to print
>> additional information when it is run. These data looks similar to ones
>> below and they seems to provide the timestamps which is great as we
>> should be able to see when what command was run. I don't have a testing
>> machine on which to run fence_ilo4 so the below example just shows how
>> it looks when it fails on timeout connecting.
>>
>> Apr 03 12:34:11 [4025] fastvm-centos-7-6-31 stonith-ng: notice:
>> stonith_action_async_done: Child process 4252 performing action
>> 'monitor' timed out with signal 15
>> Apr 03 12:34:11 [4025] fastvm-centos-7-6-31 stonith-ng: warning:
>> log_action: fence_ilo4[4252] stderr: [ 2019-04-03 12:33:51,193 INFO:
>> Executing: /usr/bin/ipmitool -I lanplus -H fe80::f6bd:8a67:7eb5:214f -p
>> 623 -U xyz -P [set] -L ADMINISTRATOR chassis power status ]
>> Apr 03 12:34:11 [4025] fastvm-centos-7-6-31 stonith-ng: warning:
>> log_action: fence_ilo4[4252] stderr: [ ]
>>
>> # pcs stonith update fence-uc-orana verbose=1
>>
>> Note: That above shows that some private data are included in logs, so
>> in case that you have there something interesting for sharing make sure
>> to strip out the sensitive data.
>>
>> 2. The version of fence-agents-ipmilan is not the latest when comparing
>> that to my CentOS 7.6 system
>> (fence-agents-ipmilan-4.2.1-11.el7_6.7.x86_64) so you may consider to
>> try upgrading the package and see if the latest provided in your
>> distribution helps by any way if that is possible.
>>
>> 3. You may check if there is any update for the iLO devices and see if
>> the updated version exhibits the same behavior with timeouts. From logs
>> I cannot tell what version or device the fence_ilo4 is communicating with.
>>
>> 4. If there is more reliable way for triggering way triggering the
>> situation when the timeout with default 20s is observed you can setup
>> network packet capture with tcpdump to see what kind of communication is
>> happening during that time. This can help to establish the idea if there
>> is any response from the iLO device while we wait which would indicate
>> the iLO or network to be issue or if the data arrives fast and the
>> fence_ilo4 doesn't do anything.
>> - In first case that would point more to network or iLO communication
>> issue
>> - In second case that would be more likely issue with fence_ilo4 or
>> ipmitool that is used for communication
>>
>> NOTE: In case that you happen to have a subscription for your systems
>> you can try also reaching technical support to look deeper on collected
>> data. That way you can save time figuring out how to strip the private
>> parts from data before sharing them here.
>>
>> ========================================================================
>>
>> --
>> Ondrej
>>
>
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