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I have a Jenkins server where I want every every build to be triggered when I commit something to master. In Github they have deploy keys which is the server's SSH key, but only a single SSH key can be used for each repository - can't use the same ssh key for multiple repositories.
Let's say
alice
is a github.com user, with 2 or more private repositories repoN
.For this example we'll work with just two repositories named repo1
and repo2
https://github.com/alice/repo1
https://github.com/alice/repo2
You need to be to pull from these repositories without entering a passwords probably on a server, or on multiple servers.You want to perform
git pull origin master
for example, and you want this to happen without asking for a password.You don't like dealing with ssh-agent, you have discovered (or you're discovering now) about
~/.ssh/config
a file that let's your ssh client know what private key to use depending on Hostname and username, with a simple configuration entry that looks like this:So you went ahead and created your
(alice_github.id_rsa, alice_github.id_rsa.pub)
keypair, you then also went to your repository's .git/config
file and you modified the url of your remote origin
to be something like this:And finally you went to the repository
Settings > Deploy keys
section and added the contents of alice_github.id_rsa.pub
At this point you could do your
git pull origin master
without entering a password without issue.but what about the second repository?
So your instinct will be to grab that key and add it to
repo2
's Deploy keys, but github.com will error out and tell you that the key is already being used.Now you go and generate another key (using
ssh-keygen -t rsa -C '[email protected]'
without passwords of course), and so that this doesn't become a mess, you will now name your keys like this:repo1
keypair:(repo1.alice_github.id_rsa, repo1.alice_github.id_rsa.pub)
repo2
keypair:(repo2.alice_github.id_rsa, repo2.alice_github.id_rsa.pub)
You will now put the new public key on
repo2
's Deploy keys configuration at github.com, but now you have an ssh problem to deal with.How can ssh tell which key to use if the repositories are hosted on the same github.com
domain?
Your
.ssh/config
file points to github.com
and it doesn't know which key to use when it's time to do the pull.So I found a trick with github.com. You can tell your ssh client that each repository lives in a different github.com subdomain, in these cases, they will be
repo1.github.com
and repo2.github.com
So first thing is editing the
.git/config
files on your repo clones, so they look like this instead:For repo1
For repo2
And then, on your
.ssh/config
file, now you will be able to enter a configuration for each subdomain :)Now you are able to
git pull origin master
without entering any passwords from both repositories.![Github Same Ssh Deploy Key Multiple Repositories Github Same Ssh Deploy Key Multiple Repositories](/uploads/1/2/5/6/125612462/694127982.png)
If you have multiple machines, you could copy the keys to each of the machines and reuse them, but I'd advise doing the leg work to generate 1 key per machine and repo. You will have a lot more keys to handle, but you will be less vulnerable if one gets compromised.