open-nomad/command/init.go
2017-08-16 23:32:41 -07:00

375 lines
14 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".
# The "job" stanza is the top-most configuration option in the job
# specification. A job is a declarative specification of tasks that Nomad
# should run. Jobs have a globally unique name, one or many task groups, which
# are themselves collections of one or many tasks.
#
# For more information and examples on the "job" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/job.html
#
job "example" {
# The "region" parameter specifies the region in which to execute the job. If
# omitted, this inherits the default region name of "global".
# region = "global"
# The "datacenters" parameter specifies the list of datacenters which should
# be considered when placing this task. This must be provided.
datacenters = ["dc1"]
# The "type" parameter controls the type of job, which impacts the scheduler's
# decision on placement. This configuration is optional and defaults to
# "service". For a full list of job types and their differences, please see
# the online documentation.
#
# For more information, please see the online documentation at:
#
# https://www.nomadproject.io/docs/jobspec/schedulers.html
#
type = "service"
# The "constraint" stanza defines additional constraints for placing this job,
# in addition to any resource or driver constraints. This stanza may be placed
# at the "job", "group", or "task" level, and supports variable interpolation.
#
# For more information and examples on the "constraint" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/constraint.html
#
# constraint {
# attribute = "${attr.kernel.name}"
# value = "linux"
# }
# The "update" stanza specifies the update strategy of task groups. The update
# strategy is used to control things like rolling upgrades, canaries, and
# blue/green deployments. If omitted, no update strategy is enforced. The
# "update" stanza may be placed at the job or task group. When placed at the
# job, it applies to all groups within the job. When placed at both the job and
# group level, the stanzas are merged with the group's taking precedence.
#
# For more information and examples on the "update" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/update.html
#
update {
# The "max_parallel" parameter specifies the maximum number of updates to
# perform in parallel. In this case, this specifies to update a single task
# at a time.
max_parallel = 1
# The "min_healthy_time" parameter specifies the minimum time the allocation
# must be in the healthy state before it is marked as healthy and unblocks
# further allocations from being updated.
min_healthy_time = "10s"
# The "healthy_deadline" parameter specifies the deadline in which the
# allocation must be marked as healthy after which the allocation is
# automatically transitioned to unhealthy. Transitioning to unhealthy will
# fail the deployment and potentially roll back the job if "auto_revert" is
# set to true.
healthy_deadline = "3m"
# The "auto_revert" parameter specifies if the job should auto-revert to the
# last stable job on deployment failure. A job is marked as stable if all the
# allocations as part of its deployment were marked healthy.
auto_revert = false
# The "canary" parameter specifies that changes to the job that would result
# in destructive updates should create the specified number of canaries
# without stopping any previous allocations. Once the operator determines the
# canaries are healthy, they can be promoted which unblocks a rolling update
# of the remaining allocations at a rate of "max_parallel".
#
# Further, setting "canary" equal to the count of the task group allows
# blue/green deployments. When the job is updated, a full set of the new
# version is deployed and upon promotion the old version is stopped.
canary = 0
}
# The "group" stanza defines a series of tasks that should be co-located on
# the same Nomad client. Any task within a group will be placed on the same
# client.
#
# For more information and examples on the "group" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/group.html
#
group "cache" {
# The "count" parameter specifies the number of the task groups that should
# be running under this group. This value must be non-negative and defaults
# to 1.
count = 1
# The "restart" stanza configures a group's behavior on task failure. If
# left unspecified, a default restart policy is used based on the job type.
#
# For more information and examples on the "restart" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/restart.html
#
restart {
# The number of attempts to run the job within the specified interval.
attempts = 10
interval = "5m"
# The "delay" parameter specifies the duration to wait before restarting
# a task after it has failed.
delay = "25s"
# The "mode" parameter controls what happens when a task has restarted
# "attempts" times within the interval. "delay" mode delays the next
# restart until the next interval. "fail" mode does not restart the task
# if "attempts" has been hit within the interval.
mode = "delay"
}
# The "ephemeral_disk" stanza instructs Nomad to utilize an ephemeral disk
# instead of a hard disk requirement. Clients using this stanza should
# not specify disk requirements in the resources stanza of the task. All
# tasks in this group will share the same ephemeral disk.
#
# For more information and examples on the "ephemeral_disk" stanza, please
# see the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/ephemeral_disk.html
#
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
#
# Setting migrate to true results in the allocation directory of a
# sticky allocation directory to be migrated.
# migrate = true
# The "size" parameter specifies the size in MB of shared ephemeral disk
# between tasks in the group.
size = 300
}
# The "task" stanza creates an individual unit of work, such as a Docker
# container, web application, or batch processing.
#
# For more information and examples on the "task" stanza, please see
# the online documentation at:
#
# https://www.nomadproject.io/docs/job-specification/task.html
#
task "redis" {
# The "driver" parameter specifies the task driver that should be used to
# run the task.
driver = "docker"
# The "config" stanza specifies the driver configuration, which is passed
# directly to the driver to start the task. The details of configurations
# are specific to each driver, so please see specific driver
# documentation for more information.
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" stanza 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, 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 "template" stanza can also be used to create environment variables
# for tasks that prefer those to config files. The task will be restarted
# when data pulled from Consul or Vault changes.
#
# template {
# data = "KEY={{ key \"service/my-key\" }}"
# destination = "local/file.env"
# env = true
# }
# 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"
}
}
}
`)