mirror of
https://github.com/offen/docker-volume-backup.git
synced 2024-11-10 00:30:29 +01:00
Frederik Ring
c3daeacecb
* Query for labeled services as well * Try scaling down services * Scale services back up * Use progress tool from Docker CLI * In test, label both services * Clean up error and log messages * Document scale-up/down approach in docs * Downgrade Docker CLI to match client * Document services stats * Do not rely on PreviousSpec for storing desired replica count * Log warnings from Docker when updating services * Check whether container and service labels collide * Document script behavior on label collision * Add additional check if all containers have been removed * Scale services concurrently * Move docker interaction code into own file * Factor out code for service updating * Time out after five minutes of not reaching desired container count * Inline handling of in-swarm container level restart * Timer is more suitable for timeout race * Timeout when scaling down services should be configurable * Choose better filename * Reflect changes in naming * Rename and deprecate BACKUP_STOP_CONTAINER_LABEL * Improve logging * Further simplify logging
82 lines
2.3 KiB
Markdown
82 lines
2.3 KiB
Markdown
---
|
|
title: Use with Docker Swarm
|
|
layout: default
|
|
parent: How Tos
|
|
nav_order: 13
|
|
---
|
|
|
|
# Use with Docker Swarm
|
|
|
|
{: .note }
|
|
The mechanisms described in this page __do only apply when Docker is running in [Swarm mode][swarm]__.
|
|
|
|
[swarm]: https://docs.docker.com/engine/swarm/
|
|
|
|
## Stopping containers during backup
|
|
|
|
Stopping and restarting containers during backup creation when running Docker in Swarm mode is supported in two ways.
|
|
|
|
{: .important }
|
|
Make sure you label your services and containers using only one of the describe approaches.
|
|
In case the script encounters a container that is labeled and has a parent service that is also labeled, it will exit early.
|
|
|
|
### Scaling services down to zero before scaling back up
|
|
|
|
When labeling a service in the `deploy` section, the following strategy for stopping and restarting will be used:
|
|
|
|
- The service is scaled down to zero replicas
|
|
- The backup is created
|
|
- The service is scaled back up to the previous number of replicas
|
|
|
|
{: .note }
|
|
This approach will only work for services that are deployed in __replicated mode__.
|
|
|
|
Such a service definition could look like:
|
|
|
|
```yml
|
|
services:
|
|
app:
|
|
image: myorg/myimage:latest
|
|
deploy:
|
|
labels:
|
|
- docker-volume-backup.stop-during-backup=true
|
|
replicas: 2
|
|
```
|
|
|
|
### Stopping the containers
|
|
|
|
This approach bypasses the services and stops containers directly, creates the backup and restarts the containers again.
|
|
As Docker Swarm would usually try to instantly restart containers that are manually stopped, this approach only works when using the `on-failure` restart policy.
|
|
A restart policy of `always` is not compatible with this approach.
|
|
|
|
Such a service definition could look like:
|
|
|
|
```yml
|
|
services:
|
|
app:
|
|
image: myapp/myimage:latest
|
|
labels:
|
|
- docker-volume-backup.stop-during-backup=true
|
|
deploy:
|
|
replicas: 2
|
|
restart_policy:
|
|
condition: on-failure
|
|
```
|
|
|
|
---
|
|
|
|
## Memory limit considerations
|
|
|
|
When running in Swarm mode, it's also advised to set a hard memory limit on your service (~25MB should be enough in most cases, but if you backup large files above half a gigabyte or similar, you might have to raise this in case the backup exits with `Killed`):
|
|
|
|
```yml
|
|
services:
|
|
backup:
|
|
image: offen/docker-volume-backup:v2
|
|
deployment:
|
|
resources:
|
|
limits:
|
|
memory: 25M
|
|
```
|
|
|