The recently concluded ContainerCon generated quite a lot of excitement around container technologies. The updates from the Linux Container (LXC) project were particularly interesting. Canonical, the company that is spearheading the work behind Ubuntu's fast dense and secure container management project, had shared the concept of Linux Container Hypervisor (LXD) last year. LXD is a new stratum on top of LXC that brings the advantages of legacy hypervisors into the modern world of containers. What is particularly important is that the LXD project provides RESTful APIs that can be used to start, stop, clone, and migrate the containers on any given host. Hosts can also run LXD clusters delivering cloud infrastructure at higher speeds and low cost. LXDs can also run along with Docker, which allows resources to be used as a pool of micro-services delivering complex web applications. The most fascinating aspect of LXD is that the underlying container technology is decoupled from the RESTful API driving the functionality which allows it to be used as a cross-functional container management layer.
The RESTful API allows communication between LXD and its clients. The calls over HTTP are encapsulated over SSL. You can do a GET / to get all the available end points. This will also give you the list of available versions. You can then do a GET to / [version]/Images/* to get the list of publicly available images. The API also supports the recursion argument to allow optimizing queries against large collections.
A GET operation on the [version]/containers API gets the list of containers. It also specifies the authentication and the operation type. A POST operation on the same API will allow you to create a container. The return type is either a background operation or an error. There are a bunch of management operations you can perform on each container by using the [version]/containers/ [name] API.
Linux, hypervisor, RESTful API, LXD, Microservices