88 lines
3.0 KiB
Markdown
88 lines
3.0 KiB
Markdown
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# Fabric
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[Fabric](https://www.fabfile.org) is a Python library for performing devops tasks. You can thing of it a bit like a
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makefile on steroids for Python. Its api abstracts away the clunky way you would run shell commands in Python, check
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return values and manage stdio. Tasks may be targetted at particular hosts or group of hosts.
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# Using Fabric
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$ cd PyBitmessage
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$ fab <task_name>
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For a list of available commands:
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$ fab -l
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General fabric commandline help
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$ fab -h
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Arguments can be given:
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$ fab task1:arg1=arg1value,arg2=arg2value task2:option1
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Tasks target hosts. Hosts can be specified with -H, or roles can be defined and you can target groups of hosts with -R.
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Furthermore, you can use -- to run arbitrary shell commands rather than tasks:
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$ fab -H localhost task1
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$ fab -R webservers -- sudo /etc/httpd restart
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# Getting started
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* Install [Fabric](http://docs.fabfile.org/en/1.14/usage/fab.html),
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[fabric-virtualenv](https://pypi.org/project/fabric-virtualenv/) and
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[virtualenvwrapper](https://virtualenvwrapper.readthedocs.io/en/latest/)
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system-wide using your preferred method.
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* Create a virtualenv called pybitmessage and install fabfile/requirements.txt
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$ mkvirtualenv -r fabfile/requirements.txt --system-site-packages pybitmessage-devops
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* Ensure you can ssh localhost with no intervention, which may include:
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* ssh [sshd_config server] and [ssh_config client] configuration
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* authorized_keys file
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* load ssh key
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* check(!) and accept the host key
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* From the PyBitmessage directory you can now run fab commands!
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# Rationale
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There are a number of advantages that should benefit us:
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* Common tasks can be writen in Python and executed consistently
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* Common tasks are now under source control
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* All developers can run the same commands, if the underlying command sequence for a task changes (after review, obv)
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the user does not have to care
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* Tasks can be combined either programmatically or on the commandline and run in series or parallel
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* Whole environments can be managed very effectively in conjunction with a configuration management system
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<a name="sshd_config"></a>
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# /etc/ssh/sshd_config
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If you're going to be using ssh to connect to localhost you want to avoid weakening your security. The best way of
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doing this is blocking port 22 with a firewall. As a belt and braces approach you can also edit the
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/etc/ssh/sshd_config file to restrict login further:
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```
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PubkeyAuthentication no
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...
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Match ::1
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PubkeyAuthentication yes
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```
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Adapted from [stackexchange](https://unix.stackexchange.com/questions/406245/limit-ssh-access-to-specific-clients-by-ip-address)
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<a name="ssh_config"></a>
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# ~/.ssh/config
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Fabric will honour your ~/.ssh/config file for your convenience. Since you will spend more time with this key unlocked
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than others you should use a different key:
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```
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Host localhost
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HostName localhost
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IdentityFile ~/.ssh/id_rsa_localhost
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Host github
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HostName github.com
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IdentityFile ~/.ssh/id_rsa_github
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```
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