/concierge

Ladies and gentlemen: maintainable SSH configs

Primary LanguagePythonMIT LicenseMIT

concierge

PyPI Build Status Code Coverage

concierge is a small utility/daemon which is intended to help humans to maintain their SSH configs.

Contents

Introduction

There is not problems with SSH config format: it works for decades and is going to work for my children I guess. This utility will die, but one will update his ~/.ssh/config to access some network server.

The problem with SSH that it really hard to scale. I am not quite sure about other people jobs, but on my current and previous jobs I was used to maintain quite large sets of records in SSH configs. Usual deployment of some modern app consist several machines (let's say X) and during development we are using several stage environments (let's say Y). So, frankly, you need to have X * Y records in your ~/.ssh/config. Only for work.

Sometimes you need to jugle with jump hosts. Sometimes your stage is moving to another set of IPs. Sometimes life happens and it is quite irritating to manage these configuration manually.

I did a lot of CSS stylesheets and SSH config management is pretty close to that. I want to have SASS for SSH config. The main goal of this tool is to provide user with some templating and clutter-free config management in SASS way.

Demo

Asciinema screencast

Installation

Installation is quite trivial:

$ pip install concierge

or if you want to install it manually, do following:

$ git clone https://github.com/9seconds/concierge.git
$ cd concierge
$ python setup.py install

By default, no template support is going to be installed. If you want to use Mako or Jinja2, please refer to Templaters section.

Also, it is possible to install support of libnotify. Please install tool like this:

$ pip install concierge[libnotify]

In that case, you will have a desktop notifications about any problem with parsing of your ~/.conciergerc. Yep, these Ubuntu popups on the right top of the screen.

If you have a problems with Pip installation (with modifiers, for example), please update your pip and setuptools first.

$ pip install --upgrade pip setuptools

Eventually there will be no such problem anywhere.

Please be noticed, that concierge is Python 3 only tool. It should work on cPython >= 3.3 without any problems. Come on, Python 3.4 is bundled even with CentOS 7!

After installation, 2 utilities will be available:

  • concierge-check
  • concierge

Templaters

concierge comes with support of additional templaters, you may plug them in installing the packages from PyPI. At the time of writing, support of following templaters was done:

To install them just do

$ pip install concierge-mako

And concierge will automatically recognizes support of Mako and now one may use concierge -u mako for her ~/.conciergerc.

concierge-check

concierge-check is a tool to verify syntax of your ~/.conciergerc file. Please check Syntax description to get on speed.

Also, it supports a number of options but they are pretty trivial.

Please remember, that both concierge-check and concierge use syslog for logging data in process. Options like --debug or --verbose will affect only stderr logging, syslog will have only errors.

concierge

concierge is intended to work in daemon mode. It converts between your ~/.conciergerc and destination ~/.ssh/config (so Installation magic work in that way).

I use systemd so concierge is bundled to support it. To get an instructions of how to use the tool with systemd, please run following:

$ concierge --systemd

It will printout an instructions. If you do not care, please run following:

$ eval "$(concierge --systemd --curlsh)"

It will install systemd user unit and run concierge daemon automatically.

concierge supports the same options and behavior as concierge-check so please track your syslog for problems.

Syntax description

Well, there is no big difference between plain old ssh_config(5) and concierge style. Base is the same so please check the table with examples to understand what is going to be converted and how.

Syntax came from the way I structure my SSH configs for a long time . Basically I am trying to keep it in the way it looks like hierarchical .

Let's grow the syntax. Consider following config

Host m
    HostName 127.0.0.1

Host me0
    HostName 10.10.0.0

Host me1
    HostName 10.10.0.1

Host m me0 me1
    Compression no
    ProxyCommand ssh -W %h:%p env1
    User nineseconds

Host *
    Compression yes
    CompressionLevel 9

So far so good. Now let's... indent!

Host m
    HostName 127.0.0.1

    Host me0
        HostName 10.10.0.0
        ProxyCommand ssh -W %h:%p env1

    Host me1
        HostName 10.10.0.1
        ProxyCommand ssh -W %h:%p env1

    Host m me0 me1
        Compression no
        User nineseconds

Host *
    Compression yes
    CompressionLevel 9

It is still valid SSH config. And valid concierge config. Probably you already do similar indentation to visually differ different server groups. Let's check what do we have here: we have prefixes, right. And most of options are quite common to the server groups (environments).

Now let's eliminate Host m me0 me1 block. This would be invalid SSH config but valid conciergerc config. Also I am going to get rid of useless prefixes and use hierarchy to determine full name (fullname = name + parent_name).

Please be noticed that all operations maintain effectively the same conciergerc config.

Host m
    Compression no
    HostName 127.0.0.1
    User nineseconds

    Host e0
        HostName 10.10.0.0
        ProxyCommand ssh -W %h:%p env1

    Host e1
        HostName 10.10.0.1
        ProxyCommand ssh -W %h:%p env1

Host *
    Compression yes
    CompressionLevel 9

Okay. Do we need rudiment Host * section? No, let's move everything on the top. Idea is the same, empty prefix is *.

Compression yes
CompressionLevel 9

Host m
    Compression no
    HostName 127.0.0.1
    User nineseconds

    Host e0
        HostName 10.10.0.0
        ProxyCommand ssh -W %h:%p env1

    Host e1
        HostName 10.10.0.1
        ProxyCommand ssh -W %h:%p env1

By the way, you may see, that indentation defines parent is the same way as Python syntax is organized. So following config is absolutely equivalent.

Compression yes

Host m
    Compression no
    HostName 127.0.0.1
    User nineseconds

    Host e0
        HostName 10.10.0.0
        ProxyCommand ssh -W %h:%p env1

    Host e1
        HostName 10.10.0.1
        ProxyCommand ssh -W %h:%p env1

CompressionLevel 9

You can also work the other way around with a star. In this example, I remove the first Host line from being generated and add that domain information to other host. Also, ProxyJump is available

Compression yes

-Host *.my.domain
    Compression no
    User tr4sk
    ProxyJump gateway

    Host server1
        User root
    Host server2

This is a basic. But if you install concierge with support of Mako or Jinja2 templates, you may use them in your ~/.conciergerc.

Compression yes
CompressionLevel 9

Host m
    Compression no
    HostName 127.0.0.1
    User nineseconds

    % for i in range(2):
    Host e${i}
        HostName 10.10.0.${i}
        ProxyCommand ssh -W %h:%p env1
    % endfor

This is a Mako template I use. Please refer Mako and Jinja2 documentation for details.

By the way, if you want to hide some host you are using for grouping only, please prefix it with - (-Host).

Examples

Here are some examples. Please do not hesitate to check Demo, pause it, look around.

Source, converted from (~/.concierge) Destination, converted to (~/.ssh/config) 
Host name
    HostName 127.0.0.1

Host name
    HostName 127.0.0.1

Compression yes

Host name
    HostName 127.0.0.1

Host name
    HostName 127.0.0.1

Host *
    Compression yes

Compression yes

Host name
    HostName 127.0.0.1

Host *
    CompressionLevel 9

Host name
    HostName 127.0.0.1

Host *
    Compression yes
    CompressionLevel 9

Compression yes

Host name
    HostName 127.0.0.1

    Host q
        ViaJumpHost env1
        HostName node-1

Host name
    HostName 127.0.0.1

Host nameq
    HostName node-1
    ProxyCommand ssh -W %h:%p env1

Host *
    Compression yes

Compression yes

-Host name
    HostName 127.0.0.1

    Host q
        ViaJumpHost env1
        HostName node-1

Host nameq
    HostName node-1
    ProxyCommand ssh -W %h:%p env1

Host *
    Compression yes

Compression yes

Host m
    User nineseconds

    % for i in range(2):
    Host e${i}
        HostName 10.10.0.${i}
        ViaJumpHost gw2
    % endfor

    Protocol 2

Host blog
    User sa

Host blog
    User sa

Host me0
    HostName 10.10.0.0
    Protocol 2
    ProxyCommand ssh -W %h:%p gw2
    User nineseconds

Host me1
    HostName 10.10.0.1
    Protocol 2
    ProxyCommand ssh -W %h:%p gw2
    User nineseconds

Host *
    Compression yes

 Compression yes

-Host \*.my.domain
     User nineseconds

     Host first
     Host second
         HostName 10.10.10.1


     Protocol 2

 Host blog
     User sa

Host blog
    User sa

Host first.my.domain
    Protocol 2
    User nineseconds
Host second.my.domain
    User nineseconds
    Protocol 2
    HostName 10.10.10.1

Host *
    Compression yes