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此仓库是为了提升国内下载速度的镜像仓库,每日同步一次。 原始仓库: https://github.com/maas/maas
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Hacking MAAS

Coding style

MAAS follows the Launchpad Python Style Guide, except where it gets Launchpad specific, and where it talks about method naming. MAAS instead adopts PEP-8 naming in all cases, so method names should usually use the lowercase_with_underscores form.

Prerequisites

Container

There's a configure-lxd-profile script in utilities, that will set up a LXD profile that is configured properly.

Dependencies

You can grab MAAS's code manually from Launchpad but Git makes it easy to fetch the last version of the code. First of all, install Git:

$ sudo apt install git

Then go into the directory where you want the code to reside and run:

$ git clone https://git.launchpad.net/maas && cd maas

MAAS depends on Postgres, isc-dhcp, bind9, and many other packages. To install everything that's needed for running and developing MAAS, run:

$ make install-dependencies

Careful: this will apt-get install many packages on your system, via sudo. It may prompt you for your password.

This will install bind9. As a result you will have an extra daemon running. If you are a developer and don't intend to run BIND locally, you can disable the daemon by inserting exit 1 at the top of /etc/default/bind9. The package still needs to be installed for tests though.

Python development dependencies are pulled automatically from PyPI in a virtualenv located under .ve.

Git Workflow

You will want to adjust your git repository of lp:maas some before you start making changes to the code. This includes setting up your own copy of the repository and making your changes in branches.

First you will want to rename the origin remote to upstream and create a new origin in your namespace.

$ git remote rename origin upstream
$ git remote add origin git+ssh://{launchpad-id}@git.launchpad.net/~{launchpad-id}/maas

Now you can make a branch and start making changes.

$ git checkout -b new-branch

Once you have made the changes you want, you should commit and push the branch to your origin.

$ git commit -m "My change" -a
$ git push origin new-branch

Now you can view that branch on Launchpad and propose it to the maas repository.

Once the branch has been merged and your done with it you can update your git repository to remove the branch.

$ git fetch upstream
$ git checkout master
$ git merge upstream/master
$ git branch -d new-branch

Optional

The PyCharm IDE is a useful tool when developing MAAS. The MAAS team does not endorse any particular IDE, but .idea project files are included with MAAS, so PyCharm is an easy choice.

Running tests

To run the whole suite:

$ make test

To run tests at a lower level of granularity:

$ ./bin/test.region src/maasserver/tests/test_api.py
$ ./bin/test.region src/maasserver/tests/test_api.py:AnonymousEnlistmentAPITest

The test runner is nose, so you can pass in options like --with-coverage and --nocapture (short option: -s). The latter is essential when using pdb so that stdout is not adulterated.

Note

When running make test through ssh from a machine with locales that are not set up on the machine that runs the tests, some tests will fail with a MismatchError and an "unsupported locale setting" message. Running locale-gen for the missing locales or changing your locales on your workstation to ones present on the server will solve the issue.

Emitting subunit

Pass the --with-subunit flag to any of the test runners (e.g. bin/test.rack) to produce a subunit stream of test results. This may be useful for parallelising test runs, or to allow later analysis of a test run. The optional --subunit-fd flag can be used to direct the results to a different file descriptor, to ensure a clean stream.

Production MAAS server debugging

When MAAS is installed from packaging it can help to enable debugging features to triage issues.

Log all API and UI exceptions

By default MAAS only logs HTTP 500 - INTERNAL_SERVER_ERROR into the regiond.log. To enable logging of all exceptions even exceptions where MAAS will return the correct HTTP status code.:

$ sudo sed -i 's/DEBUG = False/DEBUG = True/g' \
>   /usr/lib/python3/dist-packages/maasserver/djangosettings/settings.py
$ sudo service maas-regiond restart

Run regiond in foreground

It can help when debugging to run regiond a foreground process so you can interact with the regiond by placing a breakpoint in the code. Once you have placed a breakpoint into the code you want to inspect you can start the regiond process in the foreground.:

$ sudo service maas-regiond stop
$ sudo -u maas -H \
>   DJANGO_SETTINGS_MODULE=maasserver.djangosettings.settings \
>   twistd3 --nodaemon --pidfile= maas-regiond

Note

By default a MAAS installation runs 4 regiond processes at the same time. This will change it to only run 1 process in the foreground. This should only be used for debugging. Once finished the breakpoint should be removed and maas-regiond service should be started.

Run rackd in foreground

It can help when debugging to run rackd a foreground process so you can interact with the rackd by placing a breakpoint in the code. Once you have placed a breakpoint into the code you want to inspect you can start the rackd process in the foreground.:

$ sudo service maas-rackd stop
$ sudo -u maas -H /usr/bin/authbind --deep /usr/bin/twistd3 --nodaemon --pidfile= maas-rackd

Development MAAS server setup

Access to the database is configured in src/maasserver/djangosettings/development.py.

The Makefile or the test suite sets up a development database cluster inside your branch. It lives in the db directory, which gets created on demand. You'll want to shut it down before deleting a branch; see below.

First, set up the project. This fetches all the required dependencies and sets up some useful commands in bin/:

$ make

Create the database cluster and initialise the development database:

$ make syncdb

Optionally, if all you want to do is to take a look around the UI and API, without interacting with real machines or VMs, populate your database with the sample data:

$ make sampledata

You can login as a simple user using the test account (username: 'test', password: 'test') or the admin account (username: 'admin', password: 'test').

If you want to interact with real machines or VMs, it's better to use the snap. Instead of building a real snap, though, you can use 'snapcraft prime' to create the prime directory. That has all the contents of the snap, but it's in a plain directory insted of in a squashfs image. Using a directory is better for testing, since you can change the files in there and not rebuild the snap.

There's a sync-dev-snap make target to automate this:

$ make sync-dev-snap

The sync-dev-snap target creates a clean copy of your working tree (so that you don't have to run 'make clean' before building the snap) in build/dev-snap and creates the snap directory in build/dev-snap/prime.

You can now install the snap:

$ sudo snap try build/dev-snap/prime

Note that 'snap try' is used instead of 'snap install'. The maas snap should now be installed:

$ snap list
Name          Version                 Rev   Tracking  Publisher   Notes
core          16-2.41                 7713  stable    canonical✓  core
core18        20191001                1192  stable    canonical✓  base
maas          2.7.0-8077-g.7e249fbe4  x1    -         -           try
maas-cli      0.6.5                   13    stable    canonical✓  -
snapd         2.41                    4605  stable    canonical✓  snapd

Next you need to initialize the snap, just like you would normally do:

$ sudo maas init

And now you're ready to make changes to the code. After you've change some source files and want to test them out, run the sync-dev-snap target again:

$ make sync-dev-snap

You should now see that you files were synced to the prime directory. Restart the supervisor service to use the synced code:

$ sudo service snap.maas.supervisor restart

VMs or even real machines can now PXE boot off your development snap. But of course, you need to set up the networking first. If you want to do some simple testing, the easiest is to create a networking in virt-manager that has NAT, but doesn't provide DHCP. If the name of the bridge that got created is virbr1, you can expose it to your container as eth1 using the following config:

eth1:
  name: eth1
  nictype: bridged
  parent: virbr1
  type: nic

Of course, you also need to configure that eth1 interface. Since MAAS is the one providing DHCP, you need to give it a static address on the network you created. For example:

auto eth1
iface eth1 inet static
  address 192.168.100.2
  netmask 255.255.255.0

Note that your LXD host will have the .1 address and will act as a gateway for your VMs.

To shut down the database cluster and clean up all other generated files in your branch:

$ make clean

Downloading PXE boot resources

To use PXE booting, each cluster controller needs to download several files relating to PXE booting. This process is automated, but it does not start by default.

First create a superuser and start all MAAS services:

$ bin/maas-region createadmin
$ make run

Substitute your own email. The command will prompt for a choice of password.

Next, get the superuser's API key on the account preferences page in the web UI, and use it to log into MAAS at the command-line:

$ bin/maas login dev http://localhost:5240/MAAS/

Start downloading PXE boot resources:

$  bin/maas dev node-groups import-boot-images

This sends jobs to each cluster controller, asking each to download the boot resources they require. This may download dozens or hundreds of megabytes, so it may take a while. To save bandwidth, set an HTTP proxy beforehand:

$ bin/maas dev maas set-config name=http_proxy value=http://...

Running the built-in TFTP server

You will need to run the built-in TFTP server on the real TFTP port (69) if you want to boot some real hardware. By default, it's set to start up on port 5244 for testing purposes. To make it run on port 69, set the MAAS_TFTP_PORT environment variable before running make run/start:

export MAAS_TFTP_PORT=69

Then you need install and configure the authbind, so that your user can bind to port 69:

* Install the ``authbind``package:

  $ sudo apt install authbind

* Create a file ``/etc/authbind/byport/69`` that is *executable* by the
  user running MAAS.

  $ sudo touch /etc/authbind/byport/69
  $ sudo chown $USER /etc/authbind/byport/69
  $ sudo chmod u+x /etc/authbind/byport/69

Now when starting up the MAAS development webserver, "make run" and "make start" will detect authbind's presence and use it automatically.

Running the BIND daemon for real

There's a BIND daemon that is started up as part of the development service but it runs on port 5246 by default. If you want to make it run as a real DNS server on the box then set the MAAS_BIND_PORT environment variable before running make run/start:

export MAAS_BIND_PORT=53

Then as for TFTP above, create an authbind authorisation:

$ sudo touch /etc/authbind/byport/53
$ sudo chown $USER /etc/authbind/byport/53
$ sudo chmod u+x /etc/authbind/byport/53

and run as normal.

Running the cluster worker

The cluster also needs authbind as it needs to bind a socket on UDP port 68 for DHCP probing:

$ sudo touch /etc/authbind/byport/68
$ sudo chown $USER /etc/authbind/byport/68
$ sudo chmod u+x /etc/authbind/byport/68

If you omit this, nothing else will break, but you will get an error in the cluster log because it can't bind to the port.

Configuring DHCP

MAAS requires a properly configured DHCP server so it can boot machines using PXE. MAAS can work with its own instance of the ISC DHCP server, if you install the maas-dhcp package:

$ sudo apt install maas-dhcp

Note that maas-dhcpd service definition referencese the maas-rackd service, which won't be present if you run a development service. To workaround edit /lib/systemd/system/maas-dhcp.service and comment out this line:

BindsTo=maas-rackd.service

Non-interactive configuration of RBAC service authentication

For development and automating testing purposes, it's possible to configure maas with the RBAC service in a non-interactive way, with the following:

$ sudo MAAS_CANDID_CREDENTIALS=user1:password1 maas configauth --rbac-url http://<url-of-rbac>:5000 --rbac-sevice-name <maas-service-name-in-RBAC>

This will automatically handle logging in with Candid, without requiring the user to fill in the authentication form via browser.

Development services

The development environment uses daemontools to manage the various services that are required. These are all defined in subdirectories in services/.

There are familiar service-like commands:

$ make start
$ make status
$ make restart
$ make stop

The latter is a dependency of distclean so just running make distclean when you've finished with your branch is enough to stop everything.

Individual services can be manipulated too:

$ make services/rackd/@start

The @<action> pattern works for any of the services.

There's an additional special action, run:

$ make run

This starts all services up and tails their log files. When you're done, kill tail (e.g. Ctrl-c), and all the services will be stopped.

However, when used with individual services:

$ make services/regiond/@run

it does something even cooler. First it shuts down the service, then it restarts it in the foreground so you can see the logs in the console. More importantly, it allows you to use pdb, for example.

A note of caution: some of the services have slightly different behaviour when run in the foreground:

  • regiond (the webapp service) will be run with its auto-reloading enabled.

There's a convenience target for hacking regiond that starts everything up, but with regiond in the foreground:

$ make run+regiond

Apparently Django needs a lot of debugging ;)

Adding new source files

When creating a new source file, a Python module or test for example, always start with the appropriate template from the templates directory.

Database information

MAAS uses Django to manage changes to the database schema.

Be sure to have a look at Django's migration documentation before you make any change.

Changing the schema

Once you've made a model change (i.e. a change to a file in src/<application>/models/*.py) you have to run Django's makemigrations command to create a migration file that will be stored in src/<application>/migrations/builtin/.

Note that if you want to add a new model class you'll need to import it in src/<application>/models/__init__.py

Generate the migration script with:

$ ./bin/maas-region makemigrations --name description_of_the_change maasserver

This will generate a migration module named src/maasserver/migrations/builtin/<auto_number>_description_of_the_change.py. Don't forget to add that file to the project with:

$ git add src/maasserver/migrations/builtin/<auto_number>_description_of_the_change.py

To apply that migration, run:

$ make syncdb

Performing data migration

If you need to perform data migration, very much in the same way, you will need to run Django's makemigrations command. For instance, if you want to perform changes to the maasserver application, run:

$ ./bin/maas-region makemigrations --empty --name description_of_the_change maasserver

This will generate a migration module named src/maasserver/migrations/builtin/<auto_number>_description_of_the_change.py. You will need to edit that file and fill the operations list with the options that need to be performed. Again, don't forget to add that file to the project:

$ git add src/maasserver/migrations/builtin/<auto_number>_description_of_the_change.py

Once the operations have been added, apply that migration with:

$ make syncdb

Examining the database manually

If you need to get an interactive psql prompt, you can use dbshell:

$ bin/maas-region dbshell

If you need to do the same thing with a version of MAAS you have installed from the package, you can use:

$ sudo maas-region dbshell --installed

You can use the \dt command to list the tables in the MAAS database. You can also execute arbitrary SQL. For example::

maasdb=# select system_id, hostname from maasserver_node;
                 system_id                 |      hostname
-------------------------------------------+--------------------
 node-709703ec-c304-11e4-804c-00163e32e5b5 | gross-debt.local
 node-7069401a-c304-11e4-a64e-00163e32e5b5 | round-attack.local
(2 rows)

Viewing SQL queries during tests

If you need to view the SQL queries that are performed during a test, the LogSQL fixture can be used to output all the queries during the test.:

from maasserver.testing.fixtures import LogSQL
self.useFixture(LogSQL())

Sometimes you need to see where in the code that query was performed.:

from maasserver.testing.fixtures import LogSQL
self.useFixture(LogSQL(include_stacktrace=True))

Documentation

Use reST with the convention for headings as used in the Python documentation.

Updating copyright notices

Use the Bazaar Copyright Updater:

bzr branch lp:bzr-update-copyright ~/.bazaar/plugins/update_copyright
make copyright

Then commit any changes.

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