I want to update docker swarm service without down-time. The problem is that I don't have enough resources to have service replication. Is there anyway to do this?
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The default with swarm mode is to stop containers before starting new ones. There is a pull request (#30261) that was added in 17.05 to optionally start a new instance before stopping the old one. The syntax for this is:
docker service update --update-order start-first ...
This has not been added to updating stacks yet, you can track that request on issue #32586.
BMitch
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I think this doesn't work as expected with the vip mode when you curl every second, you may get 502. – Hakan Özler Aug 12 '17 at 09:56
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This is the correct answer ! and the best practice - thanks it's really help me – Yakir GIladi Edry Jan 05 '22 at 09:34
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Based on the documentation you can use order property on your docker-service file
order: Order of operations during updates :
- stop-first (old task is stopped before starting new one)
- start-first (new task is started first, and the running tasks briefly overlap) (default stop-first)
and your docker service file will be like this
version: '3.4'
services:
nginx:
image: nginx
restart: always
deploy:
restart_policy:
condition: on-failure
update_config:
order: start-first
make sure you are using version 3.4+ to make it work
Bahaa Odeh
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The type of deploy you want to do is called blue-green deployment. I recommend following the steps of this blog to do it.
German
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