[services] make snmp.timer work again and delay telemetry.service

[stepanblyschak]

Signed-off-by: Stepan Blyschak [email protected]

- What I did

- How I did it

- How to verify it

- Description for the changelog

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[stepanblyschak]

Retest vs please

[pavel-shirshov]

retest vs please

[pavel-shirshov]

retest vs please

[lguohan]

retest vs please

[yxieca]

This change broke some link between swss and snmp. I think if swss restarts, the snmp won't get restart with this change.

This link can be restored by adding snmp as a dependency service in swss service script, where we already have a few.

[yxieca]

As commented above. There is a service link between swss and snmp got broken by this change.

[pavel-shirshov]

What do you mean by "a service link"?

[stepanblyschak]

Isn't Requisite enough?

admin@r-boxer-sw01:~$ cat /etc/systemd/system/snmp.service 
[Unit]
Description=SNMP container
Requires=updategraph.service
Requisite=swss.service
After=updategraph.service swss.service syncd.service
Before=ntp-config.service
StartLimitIntervalSec=1200
StartLimitBurst=3

[Service]
ExecStartPre=/usr/bin/snmp.sh start
ExecStart=/usr/bin/snmp.sh wait
ExecStop=/usr/bin/snmp.sh stop
Restart=always
RestartSec=30
admin@r-boxer-sw01:~$ cat /etc/systemd/system/snmp.timer
[Unit]
Description=Delays snmp container until SONiC has started

[Timer]
OnBootSec=3min 30 sec
Unit=snmp.service

[Install]
WantedBy=timers.target
admin@r-boxer-sw01:~$ date
Fri Nov  1 11:59:21 UTC 2019
admin@r-boxer-sw01:~$ sudo systemctl restart swss
admin@r-boxer-sw01:~$ show log | grep systemd | grep 'Starting\|Stopping'
...
Nov  1 11:59:24.627053 r-boxer-sw01 INFO systemd[1]: Stopping DHCP relay container...
Nov  1 11:59:24.627749 r-boxer-sw01 INFO systemd[1]: Stopping SNMP container...
Nov  1 11:59:35.087238 r-boxer-sw01 INFO systemd[1]: Stopping switch state service...
Nov  1 11:59:38.222368 r-boxer-sw01 INFO systemd[1]: Stopping syncd service...
Nov  1 11:59:38.885745 r-boxer-sw01 INFO systemd[1]: Stopping Platform monitor container...
Nov  1 11:59:53.435216 r-boxer-sw01 INFO systemd[1]: Stopping TEAMD container...
Nov  1 11:59:53.940747 r-boxer-sw01 INFO systemd[1]: Stopping Router advertiser container...
Nov  1 11:59:56.403645 r-boxer-sw01 INFO systemd[1]: Starting switch state service...
Nov  1 12:00:01.941588 r-boxer-sw01 INFO systemd[1]: Starting SNMP container...
Nov  1 12:00:02.553401 r-boxer-sw01 INFO systemd[1]: Starting syncd service...
Nov  1 12:00:11.253117 r-boxer-sw01 INFO systemd[1]: Starting TEAMD container...
Nov  1 12:00:11.284966 r-boxer-sw01 INFO systemd[1]: Starting Platform monitor container...
Nov  1 12:00:14.590531 r-boxer-sw01 INFO systemd[1]: Starting DHCP relay container...
Nov  1 12:00:14.605838 r-boxer-sw01 INFO systemd[1]: Starting Router advertiser container...

[yxieca]

Thanks @stepanblyschak , can you also test stop and start? systemctrld behaves differently between (stop/start) and (restart).

[stepanblyschak]

@yxieca Looks like working correctly as it was before 'WantedBy':

stop swss:

ov  5 17:25:06.097091 r-boxer-sw01 INFO systemd[1]: Stopping DHCP relay container...
Nov  5 17:25:06.100550 r-boxer-sw01 INFO systemd[1]: Stopping SNMP container...
Nov  5 17:25:16.672164 r-boxer-sw01 INFO systemd[1]: Stopping switch state service...
Nov  5 17:25:21.501945 r-boxer-sw01 INFO systemd[1]: Stopping syncd service...
Nov  5 17:25:34.517452 r-boxer-sw01 INFO systemd[1]: Stopping TEAMD container...
Nov  5 17:25:35.114649 r-boxer-sw01 INFO systemd[1]: Stopping Router advertiser container...

start swss:

Nov  5 17:26:33.436137 r-boxer-sw01 INFO systemd[1]: Starting switch state service...
Nov  5 17:26:38.556672 r-boxer-sw01 INFO systemd[1]: Starting TEAMD container...
Nov  5 17:26:38.558935 r-boxer-sw01 INFO systemd[1]: Starting SNMP container...
Nov  5 17:26:39.194342 r-boxer-sw01 INFO systemd[1]: Starting syncd service...
Nov  5 17:26:41.447298 r-boxer-sw01 INFO systemd[1]: Starting DHCP relay container...
Nov  5 17:26:48.537948 r-boxer-sw01 INFO systemd[1]: Starting Router advertiser container...

[yxieca]

Thanks @stepanblyschak !

[yxieca]

@stepanblyschak Please create an PR for this change against 201811 branch. There are merge conflicts. I suspect due to telemetry not in 201811.

[stepanblyschak]

@yxieca I just found that you were right, start of swss does not start snmp, even though I ensured that I test this behavior on changed image. This PR requires more work and I'll try what you suggested. You can revert for now.