Puppet on mediawiki instances in deployment-prep (beta) is failing since August 3. Message when run:
Error: Could not retrieve catalog from remote server: Error 500 on SERVER: Server Error: Evaluation Error: Error while evaluating a Resource Statement, Evaluation Error: Operator '[]' is not applicable to an Undef Value. (file: /etc/puppet/modules/profile/manifests/mediawiki/mcrouter_wancache.pp, line: 69, column: 30) on node deployment-mediawiki12.deployment-prep.eqiad1.wikimedia.cloud
When looking at the specified file and line number, I see
$wikifunctions_servers = $servers_by_datacenter_category['wikifunctions'][$::site]
which was introduced in I482290db26c029b1a9494d7783a154d69fd40f82 (https://gerrit.wikimedia.org/r/c/operations/puppet/+/944248) by @Joe on Aug 1, so I'm guessing that's the cause. Hoping he can sort this out.