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通过新增Predicates&Priorities Policies来扩展default scheduler
新增Predicate Policy
- predicate Interface
plugin/pkg/scheduler/algorithm/types.go:31// FitPredicate is a function that indicates if a pod fits into an existing node.// The failure information is given by the error.type FitPredicate func(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []PredicateFailureReason, error) - Implement a predicate func
func PodFitsHostNew(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) { if len(pod.Spec.NodeName) == 0 { return true, nil, nil } node := nodeInfo.Node() if node == nil { return false, nil, fmt.Errorf("node not found") } if pod.Spec.NodeName == node.Name { return true, nil, nil } return false, []algorithm.PredicateFailureReason{ErrPodNotMatchHostName}, nil} - register the custom predicate policy with a custom name
plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go:47func init() { ... factory.RegisterAlgorithmProvider(factory.DefaultProvider, defaultPredicates(), defaultPriorities()) // Cluster autoscaler friendly scheduling algorithm. factory.RegisterAlgorithmProvider(ClusterAutoscalerProvider, defaultPredicates(), copyAndReplace(defaultPriorities(), "LeastRequestedPriority", "MostRequestedPriority")) ... factory.RegisterFitPredicate("CustomPredicatePolicy", predicates.PodFitsHostNew) ...} - rebuild kube-scheduler and restart with flag of
--policy-config-file
kube-scheduler xxxx --policy-config-file=/var/lib/kube-scheduler/policy.config
- the content of
--policy-config-filespecified file
/var/lib/kube-scheduler/policy.config{"kind" : "Policy","apiVersion" : "v1","predicates" : [ {"name" : "CustomPredicatePolicy"} ],"priorities" : [ ]} 新增Priority Policy
- Priority Interface
/Users/garnett/workspace/go/src/k8s.io/kubernetes/plugin/pkg/scheduler/algorithm/types.go// PriorityMapFunction is a function that computes per-node results for a given node.type PriorityMapFunction func(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (schedulerapi.HostPriority, error) -
Implement a predicate func
-
register the custom predicate policy with a custom name
-
rebuild kube-scheduler and restart with flag of
--policy-config-file -
the content of
--policy-config-filespecified file
/var/lib/kube-scheduler/policy.config{"kind" : "Policy","apiVersion" : "v1","predicates" : [ ],"priorities" : [ {"name" : "CumtomPriorityPolicy", "weight" : 1} ]} 新增custom scheduler，pod指定scheduler-name进行调度
- A custom scheduler can be written in any language and can be as simple or complex as you need.
- Specify the “scheduleName” in pod.spec
apiVersion: v1kind: Podmetadata: name: nginx labels: app: nginxspec: schedulerName: my-scheduler containers: - name: nginx image: nginx:1.10
Here is a very simple example of a custom scheduler written in Bash that assigns a node randomly. Note that you need to run this along with kubectl proxy for it to work.
kubectl proxy --port=8001
#!/bin/bashSERVER='localhost:8001'while true;do for PODNAME in $(kubectl --server $SERVER get pods -o json | jq '.items[] | select(.spec.schedulerName == "my-scheduler") | select(.spec.nodeName == null) | .metadata.name' | tr -d '"'); do NODES=($(kubectl --server $SERVER get nodes -o json | jq '.items[].metadata.name' | tr -d '"')) NUMNODES=${#NODES[@]} CHOSEN=${NODES[$[ $RANDOM % $NUMNODES ]]} curl --header "Content-Type:application/json" --request POST --data '{"apiVersion":"v1", "kind": "Binding", "metadata": {"name": "'$PODNAME'"}, "target": {"apiVersion": "v1", "kind": "Node", "name": "'$CHOSEN'"}}' http://$SERVER/api/v1/namespaces/default/pods/$PODNAME/binding/ echo "Assigned $PODNAME to $CHOSEN" done sleep 1done 更多关于kubernetes的深入文章，请看我或者的博客主页。