mirror of
https://github.com/kemko/nomad.git
synced 2026-01-04 01:15:43 +03:00
5dc7e7fe25
* replace outdated tutorial links * update more tutorial links * Add CE/ENT or ENT to left nav * remove ce/ent labels * revert enterprise features
222 lines
9.3 KiB
Plaintext
222 lines
9.3 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: Inspect job workloads
|
|
description: |-
|
|
Inspect jobs, allocations, and tasks in the Nomad web UI and interact
|
|
with these objects to perform operations like restart an allocation or
|
|
stop a job.
|
|
---
|
|
|
|
# Inspect job workloads
|
|
|
|
The Web UI can be a powerful companion when monitoring and debugging jobs
|
|
running in Nomad. The Web UI will list all jobs, link jobs to allocations,
|
|
allocations to client nodes, client nodes to driver health, and much more.
|
|
|
|
## List jobs
|
|
|
|
The first page you will arrive at in the Web UI is the Jobs List page. Here you
|
|
will find every job for a namespace in a region. The table of jobs is
|
|
searchable, sortable, and filterable. Each job row in the table shows basic
|
|
information, such as job name, status, type, and priority, as well as richer
|
|
information such as a visual representation of all allocation statuses.
|
|
|
|
This view will also live-update as jobs get submitted, get purged, and change
|
|
status.
|
|
|
|
[![Jobs List][img-jobs-list]][img-jobs-list]
|
|
|
|
## Filter job view
|
|
|
|
If your Nomad cluster has many jobs, it can be useful to filter the list of all
|
|
jobs down to only those matching certain facets. The Web UI has four facets you
|
|
can filter by:
|
|
|
|
1. **Type:** The type of job, including Batch, Parameterized, Periodic, Service,
|
|
and System.
|
|
|
|
1. **Status:** The status of the job, including Pending, Running, and Dead.
|
|
|
|
1. **Datacenter:** The datacenter the job is running in, including a dynamically
|
|
generated list based on the jobs in the namespace.
|
|
|
|
1. **Prefix:** The possible common naming prefix for a job, including a
|
|
dynamically generated list based on job names up to the first occurrence of
|
|
`-`, `.`, and `_`. Only prefixes that match multiple jobs are included.
|
|
|
|
[![Job Filters][img-job-filters]][img-job-filters]
|
|
|
|
## Inspect an allocation
|
|
|
|
In Nomad, allocations are the schedulable units of work. This is where runtime
|
|
metrics begin to surface. An allocation is composed of one or more tasks, and
|
|
the utilization metrics for tasks are aggregated so they can be observed at the
|
|
allocation level.
|
|
|
|
### Monitor resource utilization
|
|
|
|
Nomad has APIs for reading point-in-time resource utilization metrics for tasks
|
|
and allocations. The Web UI uses these metrics to create time-series graphs for
|
|
the current session.
|
|
|
|
When viewing an allocation, resource utilization will automatically start
|
|
logging.
|
|
|
|
[![Allocation Resource Utilization][img-alloc-resource-utilization]][img-alloc-resource-utilization]
|
|
|
|
### Review task events
|
|
|
|
When Nomad places, prepares, and starts a task, a series of task events are
|
|
emitted to help debug issues in the event that the task fails to start.
|
|
|
|
Task events are listed on the Task Detail page and live-update as Nomad handles
|
|
managing the task.
|
|
|
|
[![Task Events][img-task-events]][img-task-events]
|
|
|
|
### View rescheduled allocations
|
|
|
|
Allocations will be placed on any client node that satisfies the constraints of
|
|
the job definition. There are events, however, that will cause Nomad to
|
|
reschedule allocations, (e.g., node failures).
|
|
|
|
Allocations can be configured [in the job definition to reschedule] to a
|
|
different client node if the allocation ends in a failed status. This will
|
|
happen after the task has exhausted its [local restart attempts].
|
|
|
|
The end result of this automatic procedure is a failed allocation and that
|
|
failed allocation's rescheduled successor. Since Nomad handles all of this
|
|
automatically, the Web UI makes sure to explain the state of allocations through
|
|
icons and linking previous and next allocations in a reschedule chain.
|
|
|
|
[![Allocation Reschedule Icon][img-alloc-reschedule-icon]][img-alloc-reschedule-icon]
|
|
|
|
[![Allocation Reschedule Details][img-alloc-reschedule-details]][img-alloc-reschedule-details]
|
|
|
|
### Unhealthy driver
|
|
|
|
Given the nature of long-lived processes, it's possible for the state of the
|
|
client node an allocation is scheduled on to change during the lifespan of the
|
|
allocation. Nomad attempts to monitor pertinent conditions including driver
|
|
health.
|
|
|
|
The Web UI denotes when a driver an allocation depends on is unhealthy on the
|
|
client node the allocation is running on.
|
|
|
|
[![Allocation Unhealthy Driver][img-alloc-unhealthy-driver]][img-alloc-unhealthy-driver]
|
|
|
|
### Preempted allocations
|
|
|
|
Much like how Nomad will automatically reschedule allocations, Nomad will
|
|
automatically preempt allocations when necessary. When monitoring allocations in
|
|
Nomad, it's useful to know what allocations were preempted and what job caused
|
|
the preemption.
|
|
|
|
The Web UI makes sure to tell this full story by showing which allocation caused
|
|
an allocation to be preempted as well as the opposite: what allocations an
|
|
allocation preempted. This makes it possible to traverse down from a job to a
|
|
preempted allocation, to the allocation that caused the preemption, to the job
|
|
that the preempting allocation is for.
|
|
|
|
[![Allocation Preempter][img-alloc-preempter]][img-alloc-preempter]
|
|
|
|
[![Allocation Preempted][img-alloc-preempted]][img-alloc-preempted]
|
|
|
|
## Review task logs
|
|
|
|
A task will typically emit log information to `stdout` and `stderr`. Nomad
|
|
captures these logs and exposes them through an API. The Web UI uses these APIs
|
|
to offer `head`, `tail`, and streaming logs from the browser.
|
|
|
|
The Web UI will first attempt to directly connect to the client node the task is
|
|
running on. Typically, client nodes are not accessible from the public internet.
|
|
If this is the case, the Web UI will fall back and proxy to the client node from
|
|
the server node with no loss of functionality.
|
|
|
|
[![Task Logs][img-task-logs]][img-task-logs]
|
|
|
|
~> Not all browsers support streaming HTTP requests. In the event that streaming
|
|
is not supported, logs will still be followed using interval polling.
|
|
|
|
## Restart or stop an allocation or task
|
|
|
|
Nomad allows for restarting and stopping individual allocations and tasks. When
|
|
a task is restarted, Nomad will perform a local restart of the task. When an
|
|
allocation is stopped, Nomad will mark the allocation as complete and perform a
|
|
reschedule onto a different client node.
|
|
|
|
Both of these features are also available in the Web UI.
|
|
|
|
[![Allocation Stop and Restart][img-alloc-stop-restart]][img-alloc-stop-restart]
|
|
|
|
## Force a periodic instance
|
|
|
|
Periodic jobs are configured like a cron job. Sometimes, you might want to start
|
|
the job before the its next scheduled run time. Nomad calls this a [periodic
|
|
force] and it can be done from the Web UI on the Job Overview page for a
|
|
periodic job.
|
|
|
|
[![Periodic Force][img-periodic-force]][img-periodic-force]
|
|
|
|
## Submit a new version of a job
|
|
|
|
From the Job Definition page, a job can be edited. After clicking the Edit
|
|
button in the top-right corner of the code window, the job definition JSON
|
|
becomes editable. The edits can then be planned and scheduled.
|
|
|
|
[![Job Definition Edit][img-job-definition-edit]][img-job-definition-edit]
|
|
|
|
~> Since each job within a namespace must have a unique name, it is possible to
|
|
submit a new version of a job from the Run Job screen. Always review the plan
|
|
output.
|
|
|
|
## Monitor a deployment
|
|
|
|
When a system or service job includes the [`update` stanza], a deployment is
|
|
created upon job submission. Job deployments can be monitored in realtime from
|
|
the Web UI.
|
|
|
|
The Web UI will show as new allocations become placed, tallying towards the
|
|
expected total, and tally allocations as they become healthy or unhealthy.
|
|
|
|
Optionally, a job may use canary deployments to allow for additional health
|
|
checks or manual testing before a full roll out. If a job uses canaries and is
|
|
not configured to automatically promote the canary, the canary promotion
|
|
operation can be done from the Job Overview page in the Web UI.
|
|
|
|
[![Job Deployment with Canary Promotion][img-job-deployment-canary]][img-job-deployment-canary]
|
|
|
|
## Stop a job
|
|
|
|
Jobs can be stopped from the Job Overview page. Stopping a job will gracefully
|
|
stop all allocations, marking them as complete, and freeing up resources in the
|
|
cluster.
|
|
|
|
[![Job Stop][img-job-stop]][img-job-stop]
|
|
|
|
## Continue your exploration
|
|
|
|
Now that you have explored operations that can be performed with jobs through
|
|
the Nomad UI, learn how to inspect the state of your cluster using the Nomad UI.
|
|
|
|
[`update` stanza]: /nomad/docs/job-specification/update
|
|
[img-alloc-preempted]: /img/monitor/guide-ui-img-alloc-preempted.png
|
|
[img-alloc-preempter]: /img/monitor/guide-ui-img-alloc-preempter.png
|
|
[img-alloc-reschedule-details]: /img/monitor/guide-ui-img-alloc-reschedule-details.png
|
|
[img-alloc-reschedule-icon]: /img/monitor/guide-ui-img-alloc-reschedule-icon.png
|
|
[img-alloc-resource-utilization]: /img/monitor/guide-ui-img-alloc-resource-utilization.png
|
|
[img-alloc-stop-restart]: /img/monitor/guide-ui-img-alloc-stop-restart.png
|
|
[img-alloc-unhealthy-driver]: /img/monitor/guide-ui-img-alloc-unhealthy-driver.png
|
|
[img-job-definition-edit]: /img/monitor/guide-ui-img-job-definition-edit.png
|
|
[img-job-deployment-canary]: /img/monitor/guide-ui-img-job-deployment-canary.png
|
|
[img-job-filters]: /img/monitor/guide-ui-img-job-filters.png
|
|
[img-job-stop]: /img/monitor/guide-ui-img-job-stop.png
|
|
[img-jobs-list]: /img/monitor/guide-ui-jobs-list.png
|
|
[img-periodic-force]: /img/monitor/guide-ui-img-periodic-force.png
|
|
[img-task-events]: /img/monitor/guide-ui-img-task-events.png
|
|
[img-task-logs]: /img/monitor/guide-ui-img-task-logs.png
|
|
[in the job definition to reschedule]: /nomad/docs/job-specification/reschedule
|
|
[local restart attempts]: /nomad/docs/job-specification/restart
|
|
[periodic force]: /nomad/commands/job/periodic-force
|
|
[securing the web ui with acls]: /nomad/docs/secure/acl
|