From 7c8dc9e6d5a6ccedf257c85573c80b7eaaa8b650 Mon Sep 17 00:00:00 2001 From: Sebastiaan van Stijn Date: Tue, 13 Sep 2016 12:08:32 +0200 Subject: [PATCH] Merge pull request #25817 from sfsmithcha/update_glossary add swarm mode terms to the glossary (cherry picked from commit 027e7be3482ff314f22dafcb7a4a2ab26b1a7ad7) Signed-off-by: Misty Stanley-Jones --- docs/reference/glossary.md | 77 ++++++++++++++++++++++++++++++++++---- 1 file changed, 69 insertions(+), 8 deletions(-) diff --git a/docs/reference/glossary.md b/docs/reference/glossary.md index 22c2d36d40..d386d52bbb 100644 --- a/docs/reference/glossary.md +++ b/docs/reference/glossary.md @@ -19,7 +19,7 @@ aufs (advanced multi layered unification filesystem) is a Linux [filesystem](#fi Docker supports as a storage backend. It implements the [union mount](http://en.wikipedia.org/wiki/Union_mount) for Linux file systems. -## Base image +## base image An image that has no parent is a **base image**. @@ -153,6 +153,16 @@ installs Docker on them, then configures the Docker client to talk to them. *Also known as : docker-machine* +## node + +A [node](../swarm/how-swarm-mode-works/nodes.md) is a physical or virtual +machine running an instance of the Docker Engine in swarm mode. + +**Manager nodes** perform swarm management and orchestration duties. By default +manager nodes are also worker nodes. + +**Worker nodes** execute tasks. + ## overlay network driver Overlay network driver provides out of the box multi-host network connectivity @@ -181,15 +191,54 @@ labeled using [tags](#tag). Here is an example of the shared [nginx repository](https://hub.docker.com/_/nginx/) and its [tags](https://hub.docker.com/r/library/nginx/tags/) + +## service + +A [service](../swarm/how-swarm-mode-works/services.md) is the definition of how +you want to run your application containers in a swarm. At the most basic level +a service defines which container image to run in the swarm and which commands +to run in the container. For orchestration purposes, the service defines the +"desired state", meaning how many containers to run as tasks and constraints for +deploying the containers. + +Frequently a service is a microservice within the context of some larger +application. Examples of services might include an HTTP server, a database, or +any other type of executable program that you wish to run in a distributed +environment. + +## service discovery + +Swarm mode [service discovery](../swarm/networking.md) is a DNS component +internal to the swarm that automatically assigns each service on an overlay +network in the swarm a VIP and DNS entry. Containers on the network share DNS +mappings for the service via gossip so any container on the network can access +the service via its service name. + +You don’t need to expose service-specific ports to make the service available to +other services on the same overlay network. The swarm’s internal load balancer +automatically distributes requests to the service VIP among the active tasks. + +## swarm + +A [swarm](../swarm/index.md) is a cluster of one or more Docker Engines running in [swarm mode](#swarm-mode). + ## Swarm -[Swarm](https://github.com/docker/swarm) is a native clustering tool for Docker. -Swarm pools together several Docker hosts and exposes them as a single virtual -Docker host. It serves the standard Docker API, so any tool that already works -with Docker can now transparently scale up to multiple hosts. +Do not confuse [Docker Swarm](https://github.com/docker/swarm) with the [swarm mode](#swarm-mode) features in Docker Engine. + +Docker Swarm is the name of a standalone native clustering tool for Docker. +Docker Swarm pools together several Docker hosts and exposes them as a single +virtual Docker host. It serves the standard Docker API, so any tool that already +works with Docker can now transparently scale up to multiple hosts. *Also known as : docker-swarm* +## swarm mode + +[Swarm mode](../swarm/index.md) refers to cluster management and orchestration +features embedded in Docker Engine. When you initialize a new swarm (cluster) or +join nodes to a swarm, the Docker Engine runs in swarm mode. + ## tag A tag is a label applied to a Docker image in a [repository](#repository). @@ -197,6 +246,18 @@ tags are how various images in a repository are distinguished from each other. *Note : This label is not related to the key=value labels set for docker daemon* +## task + +A [task](../swarm/how-swarm-mode-works/services.md#tasks-and-scheduling) is the +atomic unit of scheduling within a swarm. A task carries a Docker container and +the commands to run inside the container. Manager nodes assign tasks to worker +nodes according to the number of replicas set in the service scale. + +The diagram below illustrates the relationship of services to tasks and +containers. + +![services diagram](../swarm/images/services-diagram.png) + ## Toolbox Docker Toolbox is the installer for Mac and Windows users. @@ -209,13 +270,13 @@ very lightweight and fast. Docker uses union file systems to provide the buildin blocks for containers. -## Virtual Machine +## virtual machine -A Virtual Machine is a program that emulates a complete computer and imitates dedicated hardware. +A virtual machine is a program that emulates a complete computer and imitates dedicated hardware. It shares physical hardware resources with other users but isolates the operating system. The end user has the same experience on a Virtual Machine as they would have on dedicated hardware. -Compared to to containers, a Virtual Machine is heavier to run, provides more isolation, +Compared to to containers, a virtual machine is heavier to run, provides more isolation, gets its own set of resources and does minimal sharing. *Also known as : VM*