open-nomad/command/init.go
2016-10-31 16:52:56 -04:00

262 lines
8 KiB
Go

package command
import (
"fmt"
"io/ioutil"
"os"
"strings"
)
const (
// DefaultInitName is the default name we use when
// initializing the example file
DefaultInitName = "example.nomad"
)
// InitCommand generates a new job template that you can customize to your
// liking, like vagrant init
type InitCommand struct {
Meta
}
func (c *InitCommand) Help() string {
helpText := `
Usage: nomad init
Creates an example job file that can be used as a starting
point to customize further.
`
return strings.TrimSpace(helpText)
}
func (c *InitCommand) Synopsis() string {
return "Create an example job file"
}
func (c *InitCommand) Run(args []string) int {
// Check for misuse
if len(args) != 0 {
c.Ui.Error(c.Help())
return 1
}
// Check if the file already exists
_, err := os.Stat(DefaultInitName)
if err != nil && !os.IsNotExist(err) {
c.Ui.Error(fmt.Sprintf("Failed to stat '%s': %v", DefaultInitName, err))
return 1
}
if !os.IsNotExist(err) {
c.Ui.Error(fmt.Sprintf("Job '%s' already exists", DefaultInitName))
return 1
}
// Write out the example
err = ioutil.WriteFile(DefaultInitName, []byte(defaultJob), 0660)
if err != nil {
c.Ui.Error(fmt.Sprintf("Failed to write '%s': %v", DefaultInitName, err))
return 1
}
// Success
c.Ui.Output(fmt.Sprintf("Example job file written to %s", DefaultInitName))
return 0
}
var defaultJob = strings.TrimSpace(`
# There can only be a single job definition per file. This job is named
# "example" so it will create a job with the ID and Name "example".
job "example" {
# Run the job in the global region, which is the default.
# region = "global"
# Specify the datacenters within the region this job can run in.
datacenters = ["dc1"]
# Service type jobs optimize for long-lived services. This is
# the default but we can change to batch for short-lived tasks.
# type = "service"
# Priority controls our access to resources and scheduling priority.
# This can be 1 to 100, inclusively, and defaults to 50.
# priority = 50
# Restrict our job to only linux. We can specify multiple constraints
# as needed.
# constraint {
# attribute = "${attr.kernel.name}"
# value = "linux"
# }
# Configure the job to do rolling updates
update {
# Stagger updates every 10 seconds
stagger = "10s"
# Update a single task at a time
max_parallel = 1
}
# Create a 'cache' group. Each task in the group will be scheduled
# onto the same machine.
group "cache" {
# Control the number of instances of this group. Defaults to 1.
# count = 1
# Configure the restart policy for the task group. If not provided, a
# default is used based on the job type.
restart {
# The number of attempts to run the job within the specified interval.
attempts = 10
interval = "5m"
# A delay between a task failing and a restart occurring.
delay = "25s"
# Mode controls what happens when a task has restarted "attempts"
# times within the interval. "delay" mode delays the next restart
# till the next interval. "fail" mode does not restart the task if
# "attempts" has been hit within the interval.
mode = "delay"
}
ephemeral_disk {
# When sticky is true and the task group is updated, the scheduler
# will prefer to place the updated allocation on the same node and
# will migrate the data. This is useful for tasks that store data
# that should persist across allocation updates.
# sticky = true
# Size of the shared ephemeral disk between tasks in the task group.
size = 300
}
# Define a task to run
task "redis" {
# Use Docker to run the task.
driver = "docker"
# Configure Docker driver with the image
config {
image = "redis:3.2"
port_map {
db = 6379
}
}
# The "artifact" stanza instructs Nomad to download an artifact from a
# remote source prior to starting the task. This provides a convenient
# mechanism for downloading configuration files or data needed to run the
# task. It is possible to specify the "artifact" stanza multiple times to
# download multiple artifacts.
#
# For more information and examples on the "artifact" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/artifact.html
#
# artifact {
# source = "http://foo.com/artifact.tar.gz"
# options {
# checksum = "md5:c4aa853ad2215426eb7d70a21922e794"
# }
# }
# The "logs" stana instructs the Nomad client on how many log files and
# the maximum size of those logs files to retain. Logging is enabled by
# default, but the "logs" stanza allows for finer-grained control over
# the log rotation and storage configuration.
#
# For more information and examples on the "logs" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/logs.html
#
# logs {
# max_files = 10
# max_file_size = 15
# }
# The "resources" stanza describes the requirements a task needs to
# execute. Resource requirements include memory, disk space, network,
# cpu, and more. This ensures the task will execute on a machine that
# contains enough resource capacity.
#
# For more information and examples on the "resources" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/resources.html
#
resources {
cpu = 500 # 500 MHz
memory = 256 # 256MB
network {
mbits = 10
port "db" {}
}
}
# The "service" stanza instructs Nomad to register this task as a service
# in the service discovery engine, which is currently Consul. This will
# make the service addressable after Nomad has placed it on a host and
# port.
#
# For more information and examples on the "service" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/service.html
#
service {
name = "global-redis-check"
tags = ["global", "cache"]
port = "db"
check {
name = "alive"
type = "tcp"
interval = "10s"
timeout = "2s"
}
}
# The "template" stanza instructs Nomad to manage a template, such as
# a configuration file or script. This template can optionally pull data
# from Consul or Vault to populate runtime configuration data.
#
# For more information and examples on the "template" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/template.html
#
# template {
# data = "---\nkey: {{ key \"service/my-key\" }}"
# destination = "local/file.yml"
# change_mode = "signal"
# change_signal = "SIGHUP"
# }
# The "vault" stanza instructs the Nomad client to acquire a token from
# a HashiCorp Vault server. The Nomad servers must be configured and
# authorized to communicate with Vault. By default, Nomad will inject
# The token into the job via an environment variable and make the token
# available to the "template" stanza. The Nomad client handles the renewal
# and revocation of the Vault token.
#
# For more information and examples on the "vault" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/vault.html
#
# vault {
# policies = ["cdn", "frontend"]
# change_mode = "signal"
# change_signal = "SIGHUP"
# }
# Controls the timeout between signalling a task it will be killed
# and killing the task. If not set a default is used.
# kill_timeout = "20s"
}
}
}
`)