[ClusterLabs] Antw: [EXT] Re: VirtualDomain & "deeper" monitors - what/how?

Tue Oct 26 07:53:32 EDT 2021

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, October 26th, 2021 at 03:04, Klaus Wenninger <kwenning at redhat.com> wrote:

> On Mon, Oct 25, 2021 at 9:34 PM Kyle O'Donnell <kyleo at 0b10.mx> wrote:
>
>> Finally got around to working on this.
>>
>> I spoke with someone on the #cluterslabs IRC channel who mentioned that the monitor_scripts param does indeed run at some frequency (op monitor timeout=? interval=?), not just during the "start" and "migrate_from" actions.
>>
>> The monitor_scripts param does not support scripts with command line args, just a space delimited list for running multiple scripts. This means that each VirtualDomain resource needs its own script to be able to define the ${DOMAIN_NAME}. I found that a bit annoying so I created a symlink to a wrapper script using the ${DOMAIN_NAME} as the first part of the filename and a separator for awk:
>
> The scripts being called by the monitor operation should inherit the environment from the monitor so that you should be able to use these variables.
>
> Klaus

Thanks!

I tried referencing the ${DOMAIN_NAME} variable initially but that did not work. I tried running the function that creates the variable (VirtualDomain_getconfig) it also did not work.

After some debugging it looks like the following variables are available from the parent script:
error output [ OCF_ROOT=/usr/lib/ocf ] ]
error output [ OCF_RESKEY_crm_feature_set=3.2.1 ]
error output [ HA_LOGFACILITY=daemon ]
error output [ PCMK_debug=0 ]
error output [ HA_debug=0 ]
error output [ PWD=/var/lib/pacemaker/cores ]
error output [ OCF_RESKEY_hypervisor=qemu:///system ]
error output [ HA_logfile=/var/log/pacemaker/pacemaker.log ]
error output [ HA_logfacility=daemon ]
error output [ OCF_EXIT_REASON_PREFIX=ocf-exit-reason: ]
error output [ OCF_RESOURCE_PROVIDER=heartbeat ]
error output [ PCMK_service=pacemaker-execd ]
error output [ PCMK_mcp=true ]
error output [ OCF_RESKEY_monitor_scripts=/path/to/myvmhostname____wrap_check.sh ]
error output [ OCF_RA_VERSION_MAJOR=1 ]
error output [ VALGRIND_OPTS=--leak-check=full --trace-children=no --vgdb=no --num-callers=25 --log-file=/var/lib/pacemaker/valgrind-%p --suppressions=/usr/share/pacemaker/tests/valgrind-pcmk.suppressions --gen-suppressions=all ]
error output [ HA_cluster_type=corosync ]
error output [ INVOCATION_ID=652062571c8f415a9a7a228c5ad77b20 ]
error output [ OCF_RESKEY_CRM_meta_interval=10000 ]
error output [ OCF_RESOURCE_INSTANCE=myvmhostname ]
error output [ HA_quorum_type=corosync ]
error output [ OCF_RA_VERSION_MINOR=0 ]
error output [ HA_mcp=true ]
error output [ OCF_RESKEY_config=/path/to/myvmhostname/myvmhostname.xml ]
error output [ PCMK_quorum_type=corosync ]
error output [ OCF_RESKEY_CRM_meta_name=monitor ]
error output [ OCF_RESKEY_migration_transport=ssh ]
error output [ SHLVL=1 ]
error output [ OCF_RESKEY_CRM_meta_on_node=node02 ]
error output [ PCMK_watchdog=false ]
error output [ PCMK_logfile=/var/log/pacemaker/pacemaker.log ]
error output [ OCF_RESKEY_CRM_meta_timeout=40000 ]
error output [ OCF_RESOURCE_TYPE=VirtualDomain ]
error output [ PCMK_logfacility=daemon ]
error output [ LC_ALL=C ]
error output [ HA_LOGFILE=/var/log/pacemaker/pacemaker.log ]
error output [ JOURNAL_STREAM=9:42440 ]
error output [ OCF_RESKEY_CRM_meta_on_node_uuid=2 ]
error output [ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/ucb ]
error output [ OCF_RESKEY_force_stop=false ]
error output [ PCMK_cluster_type=corosync ]
error output [ _=/usr/bin/env ]

The most helpful variables is:
error output [ OCF_RESKEY_config=/path/to/myvmhostname/myvmhostname.xml ]

So I copied part of the "VirtualDomain_getconfig" function from the resource script to populate the variable in the same way:
DOMAIN_NAME=`egrep '[[:space:]]*<name>.*</name>[[:space:]]*$' ${OCF_RESKEY_config} 2>/dev/null | sed -e 's/[[:space:]]*<name>\(.*\)<\/name>[[:space:]]*$/\1/'`

and now it's working without the hacky symlink

>> ln -s /path/to/wrapper_script.sh /path/to/wrapper/myvmhostname_____wrapper_script.sh
>>
>> and in my wrapper_script.sh:
>> #!/bin/bash
>> DOMAIN_NAME=$(basename "$0" |awk -F'____' '{print $1}')
>> /path/to/myscript.sh -H ${DOMAIN_NAME} -C guest-get-time -l 25 -w 1
>>
>> (a bit hack-y but better than creating 1 script per vm resource and modifying it with the ${DOMAIN_NAME})
>>
>> Then creating the cluster resource:
>> pcs resource create myvmhostname VirtualDomain config="/path/to/myvmhostname/myvmhostname.xml" hypervisor="qemu:///system" migration_transport="ssh" force_stop="false" monitor_scripts="/path/to/wrapper/myvmhostname_____wrapper_script.sh" meta allow-migrate="true" target-role="Stopped" op migrate_from timeout=90s interval=0s op migrate_to timeout=120s interval=0s op monitor timeout=40s interval=10s op start timeout=90s interval=0s op stop timeout=90s interval=0s
>>
>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>
>> On Sunday, June 6th, 2021 at 16:56, Kyle O'Donnell <kyleo at 0b10.mx> wrote:
>>
>>> Let me know if there is a better approach to the following problem. When the virtual machine does not respond to a state query I want the cluster to kick it
>>>
>>> I could not find any useful docs for using the nagios plugins. After reading the documentation about running a custom script via the "monitor" function in the RA I determined that would not meet my requirements as it's only run on start and migrate(unless I read it incorrectly?).
>>>
>>> Here is what I did (im on ubuntu 20.04):
>>>
>>> cp /usr/lib/ocf/resource.d/heartbeat/VirtualDomain /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain
>>>
>>> cp /usr/share/resource-agents/ocft/configs/VirtualDomain cp /usr/share/resource-agents/ocft/configs/MyVirtDomain
>>>
>>> sed -i 's/VirtualDomain/MyVirtDomain/g' /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain
>>>
>>> sed -i 's/VirtualDomain/MyVirtDomain/g' /usr/share/resource-agents/ocft/configs/MyVirtDomain
>>>
>>> edited function MyVirtDomain_status in /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain, adding the following to the status case running|paused|idle|blocked|"in shutdown")
>>>
>>> FROM
>>>
>>> running|paused|idle|blocked|"in shutdown")
>>>
>>> # running: domain is currently actively consuming cycles
>>>
>>> # paused: domain is paused (suspended)
>>>
>>> # idle: domain is running but idle
>>>
>>> # blocked: synonym for idle used by legacy Xen versions
>>>
>>> # in shutdown: the domain is in process of shutting down, but has not completely shutdown or crashed.
>>>
>>> ocf_log debug "Virtual domain $DOMAIN_NAME is currently $status."
>>>
>>> rc=$OCF_SUCCESS
>>>
>>> TO
>>>
>>> running|paused|idle|blocked|"in shutdown")
>>>
>>> # running: domain is currently actively consuming cycles
>>>
>>> # paused: domain is paused (suspended)
>>>
>>> # idle: domain is running but idle
>>>
>>> # blocked: synonym for idle used by legacy Xen versions
>>>
>>> # in shutdown: the domain is in process of shutting down, but has not completely shutdown or crashed.
>>>
>>> custom_chk=$(/path/to/myscript.sh -H $DOMAIN_NAME -C guest-get-time -l 25 -w 1)
>>>
>>> custom_rc=$?
>>>
>>> if [ ${custom_rc} -eq 0 ]; then
>>>
>>> ocf_log debug "Virtual domain $DOMAIN_NAME is currently $status."
>>>
>>> rc=$OCF_SUCCESS
>>>
>>> else
>>>
>>> ocf_log debug "Virtual domain $DOMAIN_NAME is currently ${custom_chk}."
>>>
>>> rc=$OCF_ERR_GENERIC
>>>
>>> fi
>>>
>>> The custom script uses the qemu-guest-agent in my guest, passing the parameter to grab the guest's time (seems to be most universal [windows, centos6, ubuntu, centos 7]). Runs 25 loops, sleeps 1 second between iterations, exit 0 as soon as the agent responds with the time and exit 1 after the 25th loop, which are OCF_SUCCESS and OCF_ERR_GENERIC based on docs.
>>>
>>> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
>>> =========================================================
>>>
>>> [GOOD] - myvm virsh qemu-agent-command guest-get-time output: {"return":1623011582178375000}
>>>
>>> or when its not responding:
>>>
>>> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
>>> =========================================================
>>>
>>> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>>>
>>> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>>>
>>> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>>>
>>> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>>>
>>> ... (exits after 25th or
>>>
>>> [GOOD] - myvm virsh qemu-agent-command guest-get-time output: {"return":1623011582178375000}
>>>
>>> and when the vm isnt running:
>>>
>>> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
>>> =========================================================
>>>
>>> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: failed to get domain 'myvm'
>>>
>>> I updated my test vm to use the new RA, updated the status timeout to 40s from default of 30s just in case.
>>>
>>> I'd like to be able to update the parameters to myscript.sh via crm configure edit at some point, but will figure that out later...
>>>
>>> My test:
>>>
>>> reboot the VM from within the OS, hit escape so that I enter the boot mode prompt... after ~30 seconds the cluster decides the resource is having a problem, marks it as failed, and restarts the virtual machine (on the same node -- which in my case in desirable), once the guest is back up and responding the cluster reports the VM as Started
>>>
>>> I still have plenty more testing to do and will keep the list posted on progress.
>>>
>>> -Kyle
>>>
>>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>>
>>> On Thursday, May 27th, 2021 at 05:34, Kyle O'Donnell kyleo at 0b10.mx wrote:
>>>
>>> > guest-get-fsinfo doesn't seem to work on older agents (centos6) I've found guest-get-time more universal.
>>> >
>>> > Also, found this helpful thread on using monitor_scripts which is part of the VirtualDomain RA
>>> >
>>> > https://linux-ha-dev.linux-ha.narkive.com/yxvySDA2/monitor-scripts-parameter-for-the-virtualdomain-ra-was-re-linux-ha-ocf-resource-agent-for-kvm
>>> >
>>> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>> >
>>> > On Sunday, May 16th, 2021 at 22:49, Kyle O'Donnell kyleo at 0b10.mx wrote:
>>> >
>>> > > I am thinking about using the qemu-guest-agent to run one of the available commands to determine the health of the OS inside
>>> > >
>>> > > virsh qemu-agent-command myvm --pretty '{"execute":"guest-get-fsinfo"}'
>>> > >
>>> > > https://qemu-project.gitlab.io/qemu/interop/qemu-ga-ref.html
>>> > >
>>> > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>> > >
>>> > > On Thursday, May 13th, 2021 at 01:28, Andrei Borzenkov arvidjaar at gmail.com wrote:
>>> > >
>>> > > > On 03.05.2021 09:48, Ulrich Windl wrote:
>>> > > >
>>> > > > > > > > Ken Gaillot kgaillot at redhat.com schrieb am 30.04.2021 um 16:57 in
>>> > > > > > > >
>>> > > > > > > > Nachricht
>>> > > > > > > >
>>> > > > > > > > 3acef4bc31923fb019619c713300444c2dcd354a.camel at redhat.com:
>>> > > > > > > >
>>> > > > > > > > On Fri, 2021‑04‑30 at 11:00 +0100, lejeczek wrote:
>>> > > > > >
>>> > > > > > > Hi guys
>>> > > > > > >
>>> > > > > > > I'd like to ask around for thoughts & suggestions on any
>>> > > > > > >
>>> > > > > > > semi/official ways to monitor VirtualDomain.
>>> > > > > > >
>>> > > > > > > Something beyond what included RA does ‑ such as actual
>>> > > > > > >
>>> > > > > > > health testing of and communication with VM's OS.
>>> > > > > > >
>>> > > > > > > many thanks, L.
>>> > > > > >
>>> > > > > > This use case led to a Pacemaker feature many moons ago ...
>>> > > > > >
>>> > > > > > Pacemaker supports nagios plug‑ins as a resource type (e.g.
>>> > > > > >
>>> > > > > > nagios:check_apache_status). These are service checks usually used with
>>> > > > > >
>>> > > > > > monitoring software such as nagios, icinga, etc.
>>> > > > > >
>>> > > > > > If the service being monitored is inside a VirtualDomain, named vm1 for
>>> > > > > >
>>> > > > > > example, you can configure the nagios resource with the resource meta‑
>>> > > > > >
>>> > > > > > attribute container="vm1". If the nagios check fails, Pacemaker will
>>> > > > > >
>>> > > > > > restart vm1.
>>> > > > >
>>> > > > > "check fails" mans WARNING, CRITICAL, or UNKNOWN? ;-)
>>> > > >
>>> > > > switch (rc) {
>>> > > >
>>> > > > case NAGIOS_STATE_OK:
>>> > > >
>>> > > > return PCMK_OCF_OK;
>>> > > >
>>> > > > case NAGIOS_INSUFFICIENT_PRIV:
>>> > > >
>>> > > > return PCMK_OCF_INSUFFICIENT_PRIV;
>>> > > >
>>> > > > case NAGIOS_NOT_INSTALLED:
>>> > > >
>>> > > > return PCMK_OCF_NOT_INSTALLED;
>>> > > >
>>> > > > case NAGIOS_STATE_WARNING:
>>> > > >
>>> > > > case NAGIOS_STATE_CRITICAL:
>>> > > >
>>> > > > case NAGIOS_STATE_UNKNOWN:
>>> > > >
>>> > > > case NAGIOS_STATE_DEPENDENT:
>>> > > >
>>> > > > default:
>>> > > >
>>> > > > return PCMK_OCF_UNKNOWN_ERROR;
>>> > > >
>>> > > > }
>>> > > >
>>> > > > return PCMK_OCF_UNKNOWN_ERROR;
>>> > > >
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>>> > > >
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