open-nomad/command/node_drain.go
2018-03-21 16:51:44 -07:00

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package command
import (
"fmt"
"strings"
"time"
"github.com/hashicorp/nomad/api"
"github.com/hashicorp/nomad/api/contexts"
"github.com/posener/complete"
)
var (
// defaultDrainDuration is the default drain duration if it is not specified
// explicitly
defaultDrainDuration = 1 * time.Hour
)
type NodeDrainCommand struct {
Meta
}
func (c *NodeDrainCommand) Help() string {
helpText := `
Usage: nomad node drain [options] <node>
Toggles node draining on a specified node. It is required
that either -enable or -disable is specified, but not both.
The -self flag is useful to drain the local node.
General Options:
` + generalOptionsUsage() + `
Node Drain Options:
-disable
Disable draining for the specified node.
-enable
Enable draining for the specified node.
-deadline <duration>
Set the deadline by which all allocations must be moved off the node.
Remaining allocations after the deadline are forced removed from the node.
If unspecified, a default deadline of one hour is applied.
-force
Force remove allocations off the node immediately.
-no-deadline
No deadline allows the allocations to drain off the node without being force
stopped after a certain deadline.
-ignore-system
Ignore system allows the drain to complete without stopping system job
allocations. By default system jobs are stopped last.
-self
Set the drain status of the local node.
-yes
Automatic yes to prompts.
`
return strings.TrimSpace(helpText)
}
func (c *NodeDrainCommand) Synopsis() string {
return "Toggle drain mode on a given node"
}
func (c *NodeDrainCommand) AutocompleteFlags() complete.Flags {
return mergeAutocompleteFlags(c.Meta.AutocompleteFlags(FlagSetClient),
complete.Flags{
"-disable": complete.PredictNothing,
"-enable": complete.PredictNothing,
"-deadline": complete.PredictAnything,
"-force": complete.PredictNothing,
"-no-deadline": complete.PredictNothing,
"-ignore-system": complete.PredictNothing,
"-self": complete.PredictNothing,
"-yes": complete.PredictNothing,
})
}
func (c *NodeDrainCommand) AutocompleteArgs() complete.Predictor {
return complete.PredictFunc(func(a complete.Args) []string {
client, err := c.Meta.Client()
if err != nil {
return nil
}
resp, _, err := client.Search().PrefixSearch(a.Last, contexts.Nodes, nil)
if err != nil {
return []string{}
}
return resp.Matches[contexts.Nodes]
})
}
func (c *NodeDrainCommand) Run(args []string) int {
var enable, disable, force,
noDeadline, ignoreSystem, self, autoYes bool
var deadline string
flags := c.Meta.FlagSet("node-drain", FlagSetClient)
flags.Usage = func() { c.Ui.Output(c.Help()) }
flags.BoolVar(&enable, "enable", false, "Enable drain mode")
flags.BoolVar(&disable, "disable", false, "Disable drain mode")
flags.StringVar(&deadline, "deadline", "", "Deadline after which allocations are force stopped")
flags.BoolVar(&force, "force", false, "Force immediate drain")
flags.BoolVar(&noDeadline, "no-deadline", false, "Drain node with no deadline")
flags.BoolVar(&ignoreSystem, "ignore-system", false, "Do not drain system job allocations from the node")
flags.BoolVar(&self, "self", false, "")
flags.BoolVar(&autoYes, "yes", false, "Automatic yes to prompts.")
if err := flags.Parse(args); err != nil {
return 1
}
// Check that we got either enable or disable, but not both.
if (enable && disable) || (!enable && !disable) {
c.Ui.Error(c.Help())
return 1
}
// Check that we got a node ID
args = flags.Args()
if l := len(args); self && l != 0 || !self && l != 1 {
c.Ui.Error("Node ID must be specified if -self isn't being used")
return 1
}
// Validate a compatible set of flags were set
if disable && (deadline != "" || force || noDeadline || ignoreSystem) {
c.Ui.Error("-disable can't be combined with flags configuring drain strategy")
return 1
}
if deadline != "" && (force || noDeadline) {
c.Ui.Error("-deadline can't be combined with -force or -no-deadline")
return 1
}
if force && noDeadline {
c.Ui.Error("-force and -no-deadline are mutually exclusive")
return 1
}
// Parse the duration
var d time.Duration
if force {
d = -1 * time.Second
} else if noDeadline {
d = 0
} else if deadline != "" {
dur, err := time.ParseDuration(deadline)
if err != nil {
c.Ui.Error(fmt.Sprintf("Failed to parse deadline %q: %v", deadline, err))
return 1
}
if dur <= 0 {
c.Ui.Error("A positive drain duration must be given")
return 1
}
d = dur
} else {
d = defaultDrainDuration
}
// Get the HTTP client
client, err := c.Meta.Client()
if err != nil {
c.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
return 1
}
// If -self flag is set then determine the current node.
var nodeID string
if !self {
nodeID = args[0]
} else {
var err error
if nodeID, err = getLocalNodeID(client); err != nil {
c.Ui.Error(err.Error())
return 1
}
}
// Check if node exists
if len(nodeID) == 1 {
c.Ui.Error(fmt.Sprintf("Identifier must contain at least two characters."))
return 1
}
nodeID = sanitizeUUIDPrefix(nodeID)
nodes, _, err := client.Nodes().PrefixList(nodeID)
if err != nil {
c.Ui.Error(fmt.Sprintf("Error toggling drain mode: %s", err))
return 1
}
// Return error if no nodes are found
if len(nodes) == 0 {
c.Ui.Error(fmt.Sprintf("No node(s) with prefix or id %q found", nodeID))
return 1
}
if len(nodes) > 1 {
c.Ui.Error(fmt.Sprintf("Prefix matched multiple nodes\n\n%s",
formatNodeStubList(nodes, true)))
return 1
}
// Prefix lookup matched a single node
node, _, err := client.Nodes().Info(nodes[0].ID, nil)
if err != nil {
c.Ui.Error(fmt.Sprintf("Error toggling drain mode: %s", err))
return 1
}
// Confirm drain if the node was a prefix match.
if nodeID != node.ID && !autoYes {
verb := "enable"
if disable {
verb = "disable"
}
question := fmt.Sprintf("Are you sure you want to %s drain mode for node %q? [y/N]", verb, node.ID)
answer, err := c.Ui.Ask(question)
if err != nil {
c.Ui.Error(fmt.Sprintf("Failed to parse answer: %v", err))
return 1
}
if answer == "" || strings.ToLower(answer)[0] == 'n' {
// No case
c.Ui.Output("Canceling drain toggle")
return 0
} else if strings.ToLower(answer)[0] == 'y' && len(answer) > 1 {
// Non exact match yes
c.Ui.Output("For confirmation, an exact y is required.")
return 0
} else if answer != "y" {
c.Ui.Output("No confirmation detected. For confirmation, an exact 'y' is required.")
return 1
}
}
var spec *api.DrainSpec
if enable {
spec = &api.DrainSpec{
Deadline: d,
IgnoreSystemJobs: ignoreSystem,
}
}
// Toggle node draining
if _, err := client.Nodes().UpdateDrain(node.ID, spec, nil); err != nil {
c.Ui.Error(fmt.Sprintf("Error updating drain specification: %s", err))
return 1
}
c.Ui.Output(fmt.Sprintf("Node %q drain strategy set", node.ID))
return 0
}