The basic idea behind using a distributed system (for computation or storage) is to benefit from parallel processing, usually together with data locality. Multihost deployments usually become necessary either when the capacity of a single host is insufficient (see the earlier discussion on average and maximal number of containers on a host) or when one wants to employ distributed systems such as Apache Spark, HDFS, or Cassandra. Both performance considerations and security aspects will likely influence your design decisions.
MAC DOCKER NETWORK HOST TRIAL
Get a free trial today and find answers on the fly, or master something new and useful. Join the O'Reilly online learning platform. And heres another data point: at Mesosphere, we found in various load tests on bare metal that not more than around 250 containers per host would be possible. For example, Facebook reports thatdepending on how beefy the machine isit sees on average some 10 to 40 containers per host running. This means that one host typically has several containers running on it. The relationship between a host and containers is 1: N. Simplified Docker architecture (single host) The host has the Docker daemon and client running, as depicted in FigureĀ 1, which enables you to interact with a Docker registry on the one hand (to pull/push Docker images), and on the other hand, allows you to start, stop, and inspect containers. This can either be a physical machine (e.g., a bare-metal server in your on-premise datacenter) or a VM either on-prem or in the cloud. A Docker container needs a host to run on.
MAC DOCKER NETWORK HOST HOW TO
As an introduction to networking with Docker, were going to start small, and show how quickly you need to start thinking about how to manage connections between containers. When you start working with Docker at scale, you all of a sudden need to know a lot about networking. For more on Docker networking, including an overview of multi-host networking, see the free ebook Docker Networking and Service Discovery, by Michael Hausenblas.