This task tracks putting netmon1003 (Bullseye) in service.
**Prerequisites:**
* [x] Validate in Poonton that puppet runs cleanly in Bullseye, and all services are up
* [x] Add prometheus-atlas-exporter for Bullseye in reprepo
* [x] Ensure LibreNMS dependencies are installed for Debian Bullseye https://gerrit.wikimedia.org/r/c/operations/puppet/+/810106/
* [x] Update ACLs on network devices, via Capirca https://wikitech.wikimedia.org/wiki/Homer#Capirca_%28ACL_generation%29
* [x] Add suppport for multiple backup/passive nodes in Puppet
* [x] Set netmon1003 as a backup/standby netmon host https://gerrit.wikimedia.org/r/c/operations/puppet/+/814848
* [x] Apply the role::netmon to the netmon1003 host
* [x] Confirm the netmon1003 host has DB privileges (confirmed with @Ladsgroup
* [x] Open port in the netmon1003 firewall configuration https://gerrit.wikimedia.org/r/c/operations/puppet/+/820215
* [x] Connect to the LibreNMS database
* [x] Determine what (if any) data should to be carried over from netmon1002 to netmon1003
**Failover:**
* [x] Failover to netmon1003
* [x] Sync RRDs in /srv/librenms/rrd/
* [x] Sync rancid in /var/lib/rancid/core and /var/lib/rancid/GIT
* [x] Flip DNS for LibreNMS and Smokeping from netmon1002 to netmon1003 https://gerrit.wikimedia.org/r/c/operations/dns/+/819177
* [x] Set netmon1003 as `netmon_server` and netmon1002 as a `netmon_servers_failover` in the Puppet repository https://gerrit.wikimedia.org/r/c/operations/puppet/+/819179
* [x] Add the new host as a syslog destination in homer `templates/common/system.conf` https://gerrit.wikimedia.org/r/c/operations/homer/public/+/819124
* [x] Use netmon1003's IP address for the librenms endpoint https://gerrit.wikimedia.org/r/822124
* [x] Add the netmon1003 host to the alertmanager API rw https://gerrit.wikimedia.org/r/822126
**Post-failover validations:**
* [x] Ensure metrics in the various tabs of https://librenms.wikimedia.org/poller are similar before and after the failover
* [x] Ensure no device took too long to poll an alert
* [x] Ensure graphs look healthy
* [x] Ensure there are no active Icinga alerts for the netmon1003 host
* [x] Ensure there are no red flags in the logs - https://wikitech.wikimedia.org/wiki/LibreNMS#Check_the_logs
* [x] Ensure the new rancid directory works - https://wikitech.wikimedia.org/wiki/RANCID
* [] Update all docs with mentions of netmon1002 (and maybe a link to this task in on the LibreNMS wikitech page).