109 lines
3.2 KiB
Go
109 lines
3.2 KiB
Go
package main
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// validates the droplet information
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// finds a hypervisor
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// attempts to start the virtual machine
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import (
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"errors"
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"fmt"
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"math/rand"
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"time"
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pb "go.wit.com/lib/protobuf/virtbuf"
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)
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func isClusterStable() (string, error) {
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// how long has the cluster been stable?
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// wait until it is stable. use this to throttle droplet starts
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dur := time.Since(me.unstable)
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good := fmt.Sprintln("trying to start droplet here. grid stable for: ", pb.FormatDuration(dur))
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if dur < me.unstableTimeout {
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tmp := pb.FormatDuration(me.unstableTimeout)
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err := "grid is still too unstable (unstable timeout = " + tmp + ")\n"
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return good + err, errors.New(err)
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}
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return good, nil
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}
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// for now, because sometimes this should write to stdout and
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// sometimes to http socket, it returns a string
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func Start(name string) (string, error) {
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var result string
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if s, err := isClusterStable(); err != nil {
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result += s
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return result, err
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}
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// lookup the droplet by name
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d := me.cluster.FindDropletByName(name)
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if d == nil {
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result = "can't start unknown droplet: " + name
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return result, errors.New(result)
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}
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// validate the droplet
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if err := ValidateDroplet(d); err != nil {
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result = "ValidateDroplet() failed droplet " + d.Hostname
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return result, err
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}
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// is the droplet already on?
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if d.Current.State == pb.DropletState_ON {
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result = "EVENT start droplet " + d.Hostname + " is already ON"
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return result, errors.New(result)
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}
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// make the list of hypervisors that are active and can start new droplets
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var pool []*HyperT
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for _, h := range me.hypers {
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// this droplet is set to use this and only this hypervisor
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if d.ForceHypervisor == h.pb.Hostname {
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ok, b := h.start(d)
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if ok {
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return result + b, nil
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}
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return result + b, errors.New("start " + name + " on hypervisor " + h.pb.Hostname)
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}
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// skip hypervisors marked inactive
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if h.pb.Active != true {
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result += fmt.Sprintln("hypervisor is inactive:", name, "for", h.pb.Hostname, h.pb.Active)
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continue
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}
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// the config file says this droplet should run on this hypervisor
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// attempt to start the droplet here. use this even if the hypervisor is inactive?
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if d.PreferredHypervisor == h.pb.Hostname {
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ok, b := h.start(d)
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if ok {
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return result + b, nil
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}
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return result + b, errors.New("start " + name + " on hypervisor " + h.pb.Hostname)
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}
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result += fmt.Sprintln("hypervisor ready:", name, "for", h.pb.Hostname, h.pb.Active)
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pool = append(pool, h)
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}
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// left here as an example of how to actually do random numbers
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// it's complete mathematical chaos. Randomness is simple when
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// human interaction occurs -- which is exactly what happens most
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// of the time. most random shit is bullshit. all you really need
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// is exactly this to make sure the random functions work as they
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// should. Probably, just use this everywhere in all cases. --jcarr
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rand.Seed(time.Now().UnixNano())
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a := 0
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b := len(pool)
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n := a + rand.Intn(b-a)
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result += fmt.Sprintln("pool has", len(pool), "members", "rand =", n)
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h := pool[n]
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ok, output := h.start(d)
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if ok {
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return result + output, nil
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}
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return result + output, errors.New("start " + name + " on hypervisor " + h.pb.Hostname)
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}
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