Test and use functional controller from host list. #17
Conversation
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Hi, I will certainly have beornf have the final word, just some thoughts from my side: If you already trust DRBD and LINSTOR, you might want to make your controller's storage HA (https://linbit.com/drbd-user-guide/linstor-guide-1_0-en/#s-linstor_ha) and put a OCF cluster IP on top of it (https://github.com/LINBIT/drbd-reactor/blob/master/doc/promoter.md), then it has the same IP wherever it runs. If that sounds too complicated or does not fit your particular use case, then I'd still suggest that we expose that "try to find a controller that talks to me" logic from golinstor and then call it from here. I did not check, but from what I remember it would not require too many changes in golinstor if at all? |
Hi, unfortunately, OCF cluster IP does not really fit into our use case. I've considered using golinstor client's functions, but the plugin actually uses golinstor v0.16.3, and these functions I added don't exist in that version. If there's a way to import the last version of golinstor, I can already see how to do it, and it would require a few lines to be changed in the plugin. Don't know if this is the logic "try to find a controller that talks to me" you were talking about, or if there's some other function that does this in the actual version. |
It is just a regular go module, I don't see a reason why bumping that to the latest version would make any troubles. Looking at the versions, there must have been lots of changes, but we don't break golinstor just for fun. I would expect it just works or needs minimal changes. IMO that would be the way forward, but let's wait for @beornf if would even accept such a PR in general. |
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@csoylu I think it would be best to move to the latest golinstor version in this PR. Especially if that means less duplication of logic. I'm taking a look at golinstor and will see what's changed since v0.16.3. |
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The client constructor below should be updated.
linstor-docker-volume/driver.go
Lines 134 to 135 in 24e0f4c
By passing in the controllers as seen directly below the client will internally use
findRespondingController on each HTTP request.
controllers := strings.Split(config.Controllers, ",")
return client.NewClient(client.Controllers(controllers))| @@ -115,7 +217,14 @@ func (l *LinstorDriver) newClient() (*client.Client, error) { | |||
| return nil, err | |||
| } | |||
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| baseURL, err := l.newBaseURL(config.Controllers) | |||
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This can be deleted along with the corresponding newBaseURL method.
| @@ -77,28 +80,127 @@ func NewLinstorDriver(config, node, root string) *LinstorDriver { | |||
| } | |||
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| func (l *LinstorDriver) newBaseURL(hosts string) (*url.URL, error) { | |||
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This method can be deleted as it no longer needs to be referenced.
Hello, we are a small company called Geco-iT located in south France.
We have started using this plugin in our docker environment. Being able to switch controllers in case of a controller change was essential to our use case.
So I have included the functionality to test all the given hosts, find and use the controller between them. Most of the code is from the last version of linstor.
Tests
We have tested it in our environment with three servers, one of them being controller.
Tested with:
For each test, the plugin was able to find the controller between all the given list of hosts.