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Diffstat (limited to 'doc/administration/postgresql/database_load_balancing.md')
| -rw-r--r-- | doc/administration/postgresql/database_load_balancing.md | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/doc/administration/postgresql/database_load_balancing.md b/doc/administration/postgresql/database_load_balancing.md index 1324666c32b..b03abf9881c 100644 --- a/doc/administration/postgresql/database_load_balancing.md +++ b/doc/administration/postgresql/database_load_balancing.md @@ -1,5 +1,5 @@ --- -stage: Enablement +stage: Data Stores group: Database info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments --- @@ -97,9 +97,9 @@ For example, on an environment that has PostgreSQL running on the hosts `host1.e Service discovery allows GitLab to automatically retrieve a list of PostgreSQL hosts to use. It periodically -checks a DNS A record, using the IPs returned by this record as the addresses +checks a DNS `A` record, using the IPs returned by this record as the addresses for the secondaries. For service discovery to work, all you need is a DNS server -and an A record containing the IP addresses of your secondaries. +and an `A` record containing the IP addresses of your secondaries. When using Omnibus GitLab the provided [Consul](../consul.md) service works as a DNS server and returns PostgreSQL addresses via the `postgresql-ha.service.consul` @@ -125,23 +125,23 @@ record. For example: |----------------------|---------------------------------------------------------------------------------------------------|-----------| | `nameserver` | The nameserver to use for looking up the DNS record. | localhost | | `record` | The record to look up. This option is required for service discovery to work. | | -| `record_type` | Optional record type to look up, this can be either A or SRV (GitLab 12.3 and later) | A | +| `record_type` | Optional record type to look up, this can be either `A` or `SRV` (GitLab 12.3 and later) | `A` | | `port` | The port of the nameserver. | 8600 | | `interval` | The minimum time in seconds between checking the DNS record. | 60 | | `disconnect_timeout` | The time in seconds after which an old connection is closed, after the list of hosts was updated. | 120 | | `use_tcp` | Lookup DNS resources using TCP instead of UDP | false | If `record_type` is set to `SRV`, then GitLab continues to use round-robin algorithm -and ignores the `weight` and `priority` in the record. Since SRV records usually +and ignores the `weight` and `priority` in the record. Since `SRV` records usually return hostnames instead of IPs, GitLab needs to look for the IPs of returned hostnames -in the additional section of the SRV response. If no IP is found for a hostname, GitLab -needs to query the configured `nameserver` for ANY record for each such hostname looking for A or AAAA +in the additional section of the `SRV` response. If no IP is found for a hostname, GitLab +needs to query the configured `nameserver` for `ANY` record for each such hostname looking for `A` or `AAAA` records, eventually dropping this hostname from rotation if it can't resolve its IP. -The `interval` value specifies the _minimum_ time between checks. If the A +The `interval` value specifies the _minimum_ time between checks. If the `A` record has a TTL greater than this value, then service discovery honors said -TTL. For example, if the TTL of the A record is 90 seconds, then service -discovery waits at least 90 seconds before checking the A record again. +TTL. For example, if the TTL of the `A` record is 90 seconds, then service +discovery waits at least 90 seconds before checking the `A` record again. When the list of hosts is updated, it might take a while for the old connections to be terminated. The `disconnect_timeout` setting can be used to enforce an |