6b0aed5a inadvertantly quoted the value for DataSourceSearchReplicas in Mattermost's config.json, which is supposed to be an array, causing a failure to load the data sources.
[CRIT] Failed to ping DB err:missing "=" after "[]" in connection info string"
Correct this by removing the quotes in the ERB template. Before making this change, I verified that all other handling of the values are also of Array.
[omnibus-gitlab]$ grep -Rn sql_data_source_search_replicas
files/gitlab-config-template/gitlab.rb.template:1061:# mattermost['sql_data_source_search_replicas'] = []
files/gitlab-cookbooks/gitlab/attributes/default.rb:746:default['gitlab']['mattermost']['sql_data_source_search_replicas'] = []
files/gitlab-cookbooks/gitlab/templates/default/config.json.erb:58: "DataSourceSearchReplicas": "<%= @sql_data_source_search_replicas %>"Closes #2368 (closed)
cc @stanhu