Swarm source Analysis (3)---manage cluster

The original text of the QQ space Link: http://user.qzone.qq.com/29185807/blog/1462949671 The original article csdn blog link: http://blog.csdn.net/screscent/ article/details/51374524 1, the construction process

Let's look at the construction of cluster first.

Code in Swarm\manage.go

Initialization of a cluster object

Update nodes

In addition, the cluster object is also included in the Scheduler and API server.

Explain the importance of cluster

2, Cluster

Code in Swarm\cluster\cluster.go

First look at the structural body

The two most important things in the room.

1, store, this previous article has been analyzed

2, nodes, the part that holds the node information in the cluster and communicates with the node

Look at the Newcluster function.

Now let's take a look at some of the interfaces cluster provides

Updatenodes

This is an important interface for docking with Discovery for node updates

The incoming node, traverse, connect (connect), and add (AddNode)

AddNode

Add node and store the information through the map to determine whether to add it repeatedly. function is simple

Events

Used to set the EventHandler. In the build process rollup, set up a Loghandler

Deploycontainer

Deploy a container

Create a container through node and save the information in the store after it is successfully created. Destroycontainer

Destroy a container.

Destroys container from node and, when successful, removes its information from the store.

Summary

Cluster's function is simple, it belongs to a simple management function. The specific action is still in node.

3, Node

Let's look at the structure first.

Code in Swarm\cluster\node.go

Some of the more critical things are

Containers: Used to record containers deployed on the current node

Images: Used to record mirror information on the current node

Client: This is the key, the interface for node connection

Now let's look at the container structure.

Code in Swarm\cluster\container.go

Let's look at some of the operations of node NewNode

Create node

Is the initialization of some basic parameters

Connect

After the node is built, connect is called to the node

A dockerclient is built in the code above to connect to node

For the process in the code above, let's do an analysis of one of the following

Updatespecs

In fact, this is where the members in the node structure are initialized.

Gets the Id,name,cpus, and so on, and initializes it to the node structure body

refreshcontainers

Update the container information on the node.

Obtain the container list information via dockerclient.

Updatecontainer

In the above refreshcontainers, just get to the container list, the real update is in Updatecontainer this function

After obtaining the container information, determine if the record is already there.

If there is no record, the dockerclient will be called again. Inspectcontainer get container information.

refreshimages

Used to update images information.

Call Dockerclient, get images list, and update

Refreshloop

This is a dead loop.

There are two Chan signals.

1, container Information update sync signal. The following figure is the source of the signal

2, Force timeout container Information Update Sync signal, the following figure is the timeout time

Continue with the refresh loop

If an error occurs, the images is refreshed.

If you still have an error, judge the node disconnet and print the log.

If err is not, then the healthy is determined, and if not, the reset is done. Call Stopallmonitorevents First, then call startmonitorevents

Handler

Now let's look at handler. This is critical. This provides an interface for some operations. The callback used for dockerclient. We need to see the dockerclient source.

4, Dockerclient

Code in Github.com\samalba\dockerclient\dockerclient.go

Look at the structure first.

As you can see from the above, it is a package for httpclient newdockerclient

Constructs the docketclient structure body, its most main or constructs the HttpClient

startmonitorevents

Let's take a look at what this function is for.

Here's a bit of a sign. And then called the GetEvents

Here, like node, a GET request for events was launched to obtain the event. By decoding, get event information, and then call the node in the Dockerclient to handler for event callback processing. stopallmonitorevents

Just set a bit of a flag

listimages