speeding up DNS/SSH connections in vagrant

dns tuning ssh login speedup vagrant

- Tune /etc/ssh/sshd_config

UseDNS no  # Disable DNS lookups
GSSAPIAuthentication no # Disable negotation of slow GSSAPI

don't forget to restart it, use a script provider to set it , or create it with veewee or snapshot it

- Tune Vagrantfile

    vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]

See <http://serverfault.com/questions/453185/vagrant-virtualbox-dns-10-0-2-3-not-working?rq=1>

- Logging into the vm with a regular ssh command
See <http://blog.codeboutique.com/post/creating-debian-squeeze-box-for-vagrant>

    vagrant ssh-config vmname | ssh -t -t -F/dev/stdin vmname

Use the -t -t to overcome the pseudoterminal warning

- Now use a control connnection for ssh
(as it seems that the cli invocation of vagrant takes a couple of seconds ....)

Setup the control session:

    vagrant ssh-config vmname | ssh -t -t -F/dev/stdin -o 'ControlMaster auto' -o 'ControlPath ~/.ssh/vagrant' vmname


Use it for fast login
    ssh -o 'ControlMaster auto' -o 'ControlPath ~/.ssh/vagrant' vmname 

Now it logins in a matter of milliseconds!

For those new to Vagrantfile setup, the vb.customize line needs to be in a config.vm.provider block. For example:

config.vm.provider :virtualbox do |vb|
  vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
end

And, in this case, it assumes you are using VritualBox.

Unless a name is set explicitly, change all instances of vmname in the walkthrough to default. That was a stumbling block for me.

👍 awesome, thanks!! It connects pretty much instantly now and I can conveniently issue commands to the vm, without being locked in the session. Works with OS X 10.9 as host, Ubuntu 14.04 as guest.

Can virtualbox set UseDNS no, or does that need to be configured with chef/puppet?

This has worked! From 7 seconds regular ssh to almost instant. Am on macOS Sierra 10.12.6 with Centos as guest.

On top of the above, I also copied the output of vagrant config and used echo '...content...' | ssh ... instead. This saves time since vagrant config takes time to load.

I have been looking for a solution for slow Vagrant ssh connections on Mac for months (though interrupted by daily work).

Just in case someone is in doubt, I ran vagrant ssh and then sudo vi /etc/ssh/sshd_config. Did a /GSSAPI to search where it is and added UseDNS no above the GSSAPI section and switched off GSSAPIAuthentication.