From 773765346ba543987aa64a1119fa760f0b1cbb6f Mon Sep 17 00:00:00 2001 From: Chad Smith Date: Mon, 1 Nov 2021 14:43:05 -0600 Subject: Add LXD datasource (#1040) Add DataSourceLXD which knows how to talk to the dev-lxd socket to obtain all instance metadata API: https://linuxcontainers.org/lxd/docs/master/dev-lxd. This first branch is to deliver feature parity with the existing NoCloud datasource which is currently used to intialize LXC instances on first boot. Introduce a SocketConnectionPool and LXDSocketAdapter to support performing HTTP GETs on the following routes which are surfaced by the LXD host to all containers: http://unix.socket/1.0/meta-data http://unix.socket/1.0/config/user.user-data http://unix.socket/1.0/config/user.network-config http://unix.socket/1.0/config/user.vendor-data These 4 routes minimally replace the static content provided in the following nocloud-net seed files: /var/lib/cloud/nocloud-net/{meta-data,vendor-data,user-data,network-config} The intent of this commit is to set a foundation for LXD socket communication that will allow us to build network hot-plug features by eventually consuming LXD's websocket upgrade route 1.0/events to react to network, meta-data and user-data config changes over time. In the event that no custom network-config is provided, default to the same network-config definition provided by LXD to the NoCloud network-config seed file. Supplemental features above NoCloud datasource: surface all custom instance data config keys via cloud-init query ds which aids in discoverability of features/tags/labels as well as conditional #cloud-config jinja templates operations based on custom config options. TBD: better cloud-init query support for dot-delimited keys --- doc/rtd/topics/datasources.rst | 1 + doc/rtd/topics/datasources/lxd.rst | 65 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) create mode 100644 doc/rtd/topics/datasources/lxd.rst (limited to 'doc') diff --git a/doc/rtd/topics/datasources.rst b/doc/rtd/topics/datasources.rst index f5aee1c2..0ebc0f32 100644 --- a/doc/rtd/topics/datasources.rst +++ b/doc/rtd/topics/datasources.rst @@ -39,6 +39,7 @@ The following is a list of documents for each supported datasource: datasources/exoscale.rst datasources/fallback.rst datasources/gce.rst + datasources/lxd.rst datasources/maas.rst datasources/nocloud.rst datasources/opennebula.rst diff --git a/doc/rtd/topics/datasources/lxd.rst b/doc/rtd/topics/datasources/lxd.rst new file mode 100644 index 00000000..3991a4dd --- /dev/null +++ b/doc/rtd/topics/datasources/lxd.rst @@ -0,0 +1,65 @@ +.. _datasource_lxd: + +LXD +=== + +The data source ``LXD`` allows the user to provide custom user-data, +vendor-data, meta-data and network-config to the instance without running +a network service (or even without having a network at all). This datasource +performs HTTP GETs against the `LXD socket device`_ which is provided to each +running LXD container and VM as ``/dev/lxd/sock`` and represents all +instance-metadata as versioned HTTP routes such as: + + - 1.0/meta-data + - 1.0/config/user.meta-data + - 1.0/config/user.vendor-data + - 1.0/config/user.user-data + - 1.0/config/user. + +The LXD socket device ``/dev/lxd/sock`` is only present on containers and VMs +when the instance configuration has ``security.devlxd=true`` (default). +Disabling ``security.devlxd`` configuration setting at initial launch will +ensure that cloud-init uses the :ref:`datasource_nocloud` datasource. +Disabling ``security.devlxd`` ove the life of the container will result in +warnings from cloud-init and cloud-init will keep the originally detected LXD +datasource. + +The LXD datasource provides cloud-init the opportunity to react to meta-data, +vendor-data, user-data and network-config changes and render the updated +configuration across a system reboot. + +One can manipulate what meta-data, vendor-data or user-data is provided to +the launched container using the LXD profiles or +``lxc launch ... -c =""`` at initial container launch using one of +the following keys: + + - user.meta-data: YAML metadata which will be appended to base meta-data + - user.vendor-data: YAML which overrides any meta-data values + - user.network-config: YAML representing either :ref:`network_config_v1` or + :ref:`network_config_v2` format + - user.user-data: YAML which takes preference and overrides both meta-data + and vendor-data values + - user.any-key: Custom user configuration key and value pairs can be passed to + cloud-init. Those keys/values will be present in instance-data which can be + used by both `#template: jinja` #cloud-config templates and + the `cloud-init query` command. + + +By default, network configuration from this datasource will be: + +.. code:: yaml + + version: 1 + config: + - type: physical + name: eth0 + subnets: + - type: dhcp + control: auto + +This datasource is intended to replace :ref:`datasource_nocloud` +datasource for LXD instances with a more direct support for LXD APIs instead +of static NoCloud seed files. + +.. _LXD socket device: https://linuxcontainers.org/lxd/docs/master/dev-lxd +.. vi: textwidth=78 -- cgit v1.2.3