Multiple GitHub Accounts & SSH Config_问答_开发者

I'm having some trouble getting two different SSH keys/GitHub accounts to play well together. I have the following setup:

Repos accessible from one account using git@github.com:accountname

Repos accessible from another account using git@github.com:anotheraccount

Each account has its own SSH key开发者_运维问答. Both SSH keys have been added and I have created a config file. I don't believe the config file is correct though. I'm not quite sure how to specify that repos accessed using git@github.com:accountname should use id_rsa and git@github.com:anotheraccount should use id_rsa_anotheraccount.

Andy Lester's response is accurate but I found an important extra step I needed to make to get this to work. In trying to get two profiles set up, one for personal and one for work, my ~/.ssh/config was roughly as follows:

Host me.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/me_rsa

Host work.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/work_rsa

My work profile didn't take until I did a ssh-add ~/.ssh/work_rsa. After that connections to github used the correct profile. Previously they defaulted to the first public key.

For Could not open a connection to your authentication agent when using ssh-add,
check: https://stackoverflow.com/a/17695338/1760313

I recently had to do this and had to sift through all these answers and their comments to eventually piece the information together, so I'll put it all here, in one post, for your convenience:

Step 1: ssh keys
Create any keypairs you'll need. In this example I've named me default/original 'id_rsa' (which is the default) and my new one 'id_rsa-work':

ssh-keygen -t rsa -C "stefano@work.com"

Step 2: ssh config
Set up multiple ssh profiles by creating/modifying ~/.ssh/config. Note the slightly differing 'Host' values:

# Default GitHub
Host github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/id_rsa

# Work GitHub
Host work.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/id_rsa_work

Step 3: ssh-add
You may or may not have to do this. To check, list identity fingerprints by running:

$ ssh-add -l
2048 1f:1a:b8:69:cd:e3:ee:68:e1:c4:da:d8:96:7c:d0:6f stefano (RSA)
2048 6d:65:b9:3b:ff:9c:5a:54:1c:2f:6a:f7:44:03:84:3f stefano@work.com (RSA)

If your entries aren't there then run:

ssh-add ~/.ssh/id_rsa_work

Step 4: test
To test you've done this all correctly, I suggest the following quick check:

$ ssh -T git@github.com
Hi stefano! You've successfully authenticated, but GitHub does not provide shell access.

$ ssh -T git@work.github.com
Hi stefano! You've successfully authenticated, but GitHub does not provide shell access.

Note that you'll have to change the hostname (github / work.github) depending on what key/identity you'd like to use. But now you should be good to go! :)

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:

Host github.com
  HostName github.com
  User git
  IdentityFile /home/alice/.ssh/alice_github.id_rsa
  IdentitiesOnly yes

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:

[remote "origin"]
        url = "ssh://git@github.com/alice/repo1.git"

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 "alice@alice.com" 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

[remote "origin"]
        url = "ssh://git@repo1.github.com/alice/repo1.git"

For repo2

[remote "origin"]
        url = "ssh://git@repo2.github.com/alice/repo2.git"

And then, on your .ssh/config file, now you will be able to enter a configuration for each subdomain :)

Host repo1.github.com
  HostName github.com
  User git
  IdentityFile /home/alice/.ssh/repo1.alice_github.id_rsa
  IdentitiesOnly yes

Host repo2.github.com
  HostName github.com
  User git
  IdentityFile /home/alice/.ssh/repo2.alice_github.id_rsa
  IdentitiesOnly yes

Now you are able to git pull origin master without entering any passwords from both repositories.

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.

I have 2 accounts on github, and here is what I did (on linux) to make it work.

Keys

Create 2 pair of rsa keys, via ssh-keygen, name them properly, so that make life easier.
Add private keys to local agent via ssh-add path_to_private_key
For each github account, upload a (distinct) public key.

Configuration

~/.ssh/config

Host github-kc
    Hostname        github.com
    User git
    IdentityFile    ~/.ssh/github_rsa_kc.pub
    # LogLevel DEBUG3

Host github-abc
    Hostname        github.com
    User git
    IdentityFile    ~/.ssh/github_rsa_abc.pub
    # LogLevel DEBUG3

Set remote url for repo:

For repo in Host github-kc:

git remote set-url origin git@github-kc:kuchaguangjie/pygtrans.git

For repo in Host github-abc:

git remote set-url origin git@github-abc:abcdefg/yyy.git

Explaination

Options in ~/.ssh/config:

Host github-<identify_specific_user>
Host could be any value that could identify a host plus an account, it don't need to be a real host, e.g github-kc identify one of my account on github for my local laptop,

When set remote url for a git repo, this is the value to put after git@, that's how a repo maps to a Host, e.g git remote set-url origin git@github-kc:kuchaguangjie/pygtrans.git
[Following are sub options of Host]
Hostname
specify the actual hostname, just use github.com for github,
User git
the user is always git for github,
IdentityFile
specify key to use, just put the path the a public key,
LogLevel
specify log level to debug, if any issue, DEBUG3 gives the most detailed info.

Use the IdentityFile parameter in your ~/.ssh/config:

Host github.com
    HostName github.com
    IdentityFile ~/.ssh/github.rsa
    User petdance

A possibly simpler alternative to editing the ssh config file (as suggested in all other answers), is to configure an individual repository to use a different (e.g. non-default) ssh key.

Inside the repository for which you want to use a different key, run:

git config core.sshCommand 'ssh -i ~/.ssh/id_rsa_anotheraccount'

If your key is passhprase-protected and you don't want to type your password every time, you have to add it to the ssh-agent. Here's how to do it for ubuntu and here for macOS.

^{It should also be possible to scale this approach to multiple repositories using global git config and conditional includes (see example).}

I spent a lot of time to understand all the steps. So lets describe step by step:

Create new identity file using ssh-keygen -t rsa. Give it an alternative like proj1.id_rsa and hit with no doubt because you don't need a passphrase.

Add new section in .ssh/config:

Host proj1.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/proj1.id_rsa

Take into account the first section and note that proj1.github.com we will back to the section later.

Add the identity to ssh agent ssh-add ~/.ssh/proj1.id_rsa
That what I messed first time - now when you want to clone a proj1 repo you do it using proj1.github.com (exactly the host from the config file). git clone git@proj1.github.com.

A good tutorial.

Don't mess up with hosts

In my case none of the solutions above solved my issue, but ssh-agent does. Basically, I did the following:

Generate key pair using ssh-keygen shown below. It will generate a key pair (in this example .\keyfile and .\keyfile.pub)

ssh-keygen -t rsa -b 4096 -C "yourname@yourdomain" -f keyfile
Upload keyfile.pub to the git provider
Start ssh-agent on your machine (you can check with ps -ef | grep ssh-agent to see if it is running already)
Run ssh-add .\keyfile to add credentials
Now you can run git clone git@provider:username/project.git

As a complement of @stefano 's answer, It is better to use command with -f when generate a new SSH key for another account,

ssh-keygen -t rsa -f ~/.ssh/id_rsa_work -C "your@mail.com"

Since id_rsa_work file doesn't exist in path ~/.ssh/, and I create this file manually, and it doesn't work :(

I used,

Host github.com
   HostName github.com
   IdentityFile ~/.ssh/github_rsa
   User abc@gmail.com

It wokred fine.

Use the above setting in your .ssh/config file for different rsa keys for different usernames.

I posted the technique I use to deal with these here

Simplest way to use multiple Git accounts and clone without any changes would be to add your username to the ssh config.

Open ~/.ssh/config. Create if one doesn't exist
Add your host entry as following

Host github.com:<YOUR_GITHUB_USERNAME>
  AddKeysToAgent yes
  IdentityFile ~/.ssh/<YOUR_SSH_KEY_FILENAME>

Replace <YOUR_GITHUB_USERNAME> with your desired github username (personal or work) Replace <YOUR_SSH_KEY_FILENAME> with your keyfile name in .ssh folder (ex: id_ed25519). Add a host record for each of the github account you want to maintain.

Now git clone would be simple as git clone github.com:<YOUR_GITHUB_USERNAME>/your-repo.git. No custom gihub domains to remember when cloning ;-)

Made a gist with further information https://gist.github.com/udantha/fed5439630eaf4651272f4fba6e1c6a3