[services] make snmp.timer work again and delay telemetry.service (#3742)

Delay CPU intensive services at boot

- How I did it
Made snmp.timer work and add telemetry.timer.
But this is not enough because it breaks the existing snmp dependency on swss.
So, in this solution snmp timer is a wanted by swss service, but since OnBootSec timer expires only once it will not trigger snmp service, so I added line "OnUnitActiveSec=0 sec" which will start snmp service based on the last time it was active. On boot only OnBootSec will expire, on swss start/restarts only second timer will expire immediately and trigger snmp service.
However, snmp service will not stop after "systemctl stop snmp" because of the second timer which will always expire when snmp service because unavailable.
So there is a conflict which will be handled by systemd if we add "Conflicts=" line to both snmp.service and snmp.timer.

So during boot:

snmp does not start by default
swss starts and starts snmp timer
OnUnitActiveSec=0 does not expire since there is no snmp active
OnBootSec expires and starts snmp service and snmp timer gets stopped
During "systemctl restart swss"

snmp stops because of Requisite on swss
snmp unblocks snmp timer from running
swss starts and starts snmp timer
OnUnitActiveSec=0 expires imidiately and start snmp which stops snmp timer
During "systemctl stop snmp"

stop of snmp service unblocks snmp timer but no one starts the timer so it is not started by "OnUnitActiveSec=0"
This commit is contained in:
Stepan Blyshchak 2019-12-16 19:07:05 +02:00 committed by lguohan
parent 1e5d25b48e
commit 4ba0ff25d2
6 changed files with 20 additions and 7 deletions

View File

@ -4,6 +4,7 @@ Requires=updategraph.service
Requisite=swss.service
After=updategraph.service swss.service syncd.service
Before=ntp-config.service
Conflicts=snmp.timer
StartLimitIntervalSec=1200
StartLimitBurst=3
@ -14,5 +15,3 @@ ExecStop=/usr/bin/{{docker_container_name}}.sh stop
Restart=always
RestartSec=30
[Install]
WantedBy=multi-user.target swss.service

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@ -1,9 +1,11 @@
[Unit]
Description=Delays snmp container until SONiC has started
Conflicts=snmp.service
[Timer]
OnUnitActiveSec=0 sec
OnBootSec=3min 30 sec
Unit=snmp.service
[Install]
WantedBy=timers.target
WantedBy=timers.target swss.service

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@ -359,7 +359,7 @@ EOF
## Bind docker path
if [[ $CONFIGURED_ARCH == armhf || $CONFIGURED_ARCH == arm64 ]]; then
sudo mkdir -p $FILESYSTEM_ROOT/dockerfs
sudo mount --bind dockerfs $FILESYSTEM_ROOT/dockerfs
sudo mount --bind dockerfs $FILESYSTEM_ROOT/dockerfs
fi
{% if installer_images.strip() -%}
@ -376,7 +376,7 @@ sudo LANG=C chroot $FILESYSTEM_ROOT docker $SONIC_NATIVE_DOCKERD_FOR_DOCKERFS ta
{% endif %}
{% endfor %}
if [[ $CONFIGURED_ARCH == armhf || $CONFIGURED_ARCH == arm64 ]]; then
sudo umount $FILESYSTEM_ROOT/dockerfs
sudo umount $FILESYSTEM_ROOT/dockerfs
sudo rm -fr $FILESYSTEM_ROOT/dockerfs
sudo kill -9 `sudo $SONIC_NATIVE_DOCKERD_FOR_DOCKERFS_PID` || true
else
@ -404,6 +404,10 @@ sudo LANG=C cp $SCRIPTS_DIR/syncd.sh $FILESYSTEM_ROOT/usr/local/bin/syncd.sh
# It implements delayed start of services
sudo cp $BUILD_TEMPLATES/snmp.timer $FILESYSTEM_ROOT/etc/systemd/system/
sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable snmp.timer
{% if enable_system_telemetry == 'y' %}
sudo cp $BUILD_TEMPLATES/telemetry.timer $FILESYSTEM_ROOT/etc/systemd/system/
sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable telemetry.timer
{% endif %}
sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get purge -y python-dev
sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get clean -y

View File

@ -14,5 +14,3 @@ ExecStop=/usr/bin/{{docker_container_name}}.sh stop
Restart=always
RestartSec=30
[Install]
WantedBy=multi-user.target

View File

@ -0,0 +1,9 @@
[Unit]
Description=Delays telemetry container until SONiC has started
[Timer]
OnBootSec=3min 30 sec
Unit=telemetry.service
[Install]
WantedBy=timers.target

View File

@ -641,6 +641,7 @@ $(addprefix $(TARGET_PATH)/, $(SONIC_INSTALLERS)) : $(TARGET_PATH)/% : \
export sonic_asic_platform="$(patsubst %-$(CONFIGURED_ARCH),%,$(CONFIGURED_PLATFORM))"
export enable_organization_extensions="$(ENABLE_ORGANIZATION_EXTENSIONS)"
export enable_dhcp_graph_service="$(ENABLE_DHCP_GRAPH_SERVICE)"
export enable_system_telemetry="$(ENABLE_SYSTEM_TELEMETRY)"
export enable_ztp="$(ENABLE_ZTP)"
export shutdown_bgp_on_start="$(SHUTDOWN_BGP_ON_START)"
export enable_pfcwd_on_start="$(ENABLE_PFCWD_ON_START)"