Eksctl: Add flag to save cloudformation template to a file

[danielwhatmuff]

Why do you want this feature?
To be able to inspect/version control the raw cloudformation template. Different versions of eksctl may generate a different template based on the same eksctl configuration so this would also allow for a more reliable rollback if issues are encountered.

What feature/behavior/change do you want?
A flag to indicate that eksctl should write the rendered cloudformation template (and parameters) to a specified local file just before they are posted to the cloudformation API. A check for the flag somewhere in here https://github.com/weaveworks/eksctl/blob/5963d76300ab76f22de208018eb0567d8f76974b/pkg/cfn/manager/api.go#L115

This would support something like eks create cluster -f config.yml --write-cfnconfig string

Interested to get feedback and if positive I can PR.

[alanoberto]

Waiting for it!!!

[danielwhatmuff]

Waiting for it!!!

Ok will take a look

[pbaezab]

+1

[felipelagosn]

+1

[sayboras]

Very useful feature 💯

[martina-if]

duplicate of #956

Thanks @danielwhatmuff for reporting this. It seems like it's a useful feature. For the sake of keeping the list of issues cleaner I will close this one and keep #956 open. Please upvote it, that will help it being prioritized.

[danielwhatmuff]

No worries, I did make a start on this PR last week but my day job got in the way. Will finish off later this week if I don't see it WIP elsewhere.

[martina-if]

@danielwhatmuff some things that might be useful #718 #1039

[danielwhatmuff]

Thanks, I was following the pattern used for the write kubeconfig flag but this is also useful.

[martina-if]

@danielwhatmuff I am not sure what pattern is best in this case. I didn't really give it much thought, if you want to be sure before opening the PR please reach us on slack