How to deploy secondary / stand-by Discourse?

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The discussion revolves around deploying a secondary/stand-by Discourse setup. lejeczek is trying to set up a read-only node for both Redis and PostgreSQL but is encountering an error when Discourse attempts to write to the read-only replica.

lejeczek and pfaffman discuss the possibility of achieving high availability (HA) setup through PostgreSQL replication and potentially Redis replication. pfaffman suggests using guides from elsewhere, configuring web-only containers, and utilizing haproxy to handle the switch.

lejeczek notes the lack of official support for multi-master pgSQL and Redis, and proposes the idea of “enhancing” Discourse to allow it to run on read-only data without failing.

1

Hi guys.
How does one deploy secondary/stand-by Discourse?
I thought that would be rather a common topic but I failed to find anything on that.

Such a stand-by Discourse would be - obviously, in my mind, thus trying to set it up that way - running on a slave/-read-only node(s), read-only both for Redis & pgSQL. But Discourse fails to start with:

Redis::CommandError: ERR Error running script (call to f_bcec1d9b3bbcfb089dc0b7316771be9f011872b6): @user_script:8: @user_script: 8: -READONLY You can’t write against a read only replica.

even with DISCOURSE_SKIP_BOOTSTRAP=yes

How do you guys do that - this is all in/about containers - is it possible to have such a stand-by Discourse - the way I’m trying or any other approach - have aka HA setup?

2

If you want ha then you’d configure postgres to replicate, and maybe redis as well, though it’s not a big problem to just start with a new redis.

There are guides about setting up postgres replication elsewhere. Or you could get rds to do it for you.

Then you’d configure two web_only containers (Move from standalone container to separate web and data containers.

You’d then need to have haproxy or something to handle the switch.

It’s really beyond the help you can get here unless cyou’re stuck on the discourse part of things.

3

From what I understand, there is no official non-third-party tech to do multi-master pgSQL & even more so that applies to Redis.

Is it really not possible to tell Discourse about such environment and tell it not to worry about it &| ignore it?
If it’s not and @devel read this, then I suggest - many I’d think will appreciate - to “enhance” Discourse that way - so it does all the necessary checks but does not fail but starts & run on such read-only “data”.