Docker Swarm Code Analysis Note (+)--node structure

This is a creation in Article, where the information may have evolved or changed.

Docker Swarmschedulerwill choose to meet the requirements node to create container :

candidates, err := s.selectNodesForContainer(nodes, config, true)

nodeDefined in scheduler/node/node.go :

// Node is an abstract type used by the scheduler.type Node struct {    ID         string    IP         string    Addr       string    Name       string    Labels     map[string]string    Containers cluster.Containers    Images     []*cluster.Image    UsedMemory  int64    UsedCpus    int64    TotalMemory int64    TotalCpus   int64    HealthIndicator int64}

Cluster.listNodesThe method is implemented as follows:

// listNodes returns all validated engines in the cluster, excluding pendingEngines.func (c *Cluster) listNodes() []*node.Node {    c.RLock()    defer c.RUnlock()    out := make([]*node.Node, 0, len(c.engines))    for _, e := range c.engines {        node := node.NewNode(e)        for _, pc := range c.pendingContainers {            if pc.Engine.ID == e.ID && node.Container(pc.Config.SwarmID()) == nil {                node.AddContainer(pc.ToContainer())            }        }        out = append(out, node)    }    return out}

is actually from the Cluster.engines build node list (because it's still in a Cluster.pendingEngines pending state). The following scheduler will node select the appropriate one from this list node .