How To Securely Manage Secrets with HashiCorp Vault on Ubuntu 16.04
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Introduction

When issues come up, sending alerts to the suitable staff considerably accelerates figuring out the foundation reason for a problem, permitting groups to resolve incidents shortly.

Prometheus is an open-source monitoring system that collects metrics out of your companies and shops them in a time-series database. Alertmanager is a instrument for processing alerts, which de-duplicates, teams, and sends alerts to the suitable receiver. It could deal with alerts from shopper purposes equivalent to Prometheus, and it helps many receivers together with e-mail, PagerDuty, OpsGenie and Slack.

Because of the various Prometheus exporters out there, you possibly can configure alerts for each a part of your infrastructure, together with net and database servers, messaging programs or APIs.

Blackbox Exporter probes endpoints over HTTP, HTTPS, DNS, TCP or ICMP protocols, returning detailed metrics in regards to the request, together with whether or not or not it was profitable and the way lengthy it took to obtain a response.

On this tutorial you will set up and configure Alertmanager and Blackbox Exporter to watch the responsiveness of an Nginx net server. You will then configure Alertmanager to inform you over e-mail and Slack in case your server is not responding.

Conditions

For this tutorial, you will want:

Step 1 — Creating Service Customers

For safety functions, we’ll create two new consumer accounts, blackbox_exporter and alertmanager. We’ll use these accounts all through the tutorial to run Blackbox Exporter and Alertmanager, in addition to to isolate the possession on acceptable core recordsdata and directories. This ensures Blackbox Exporter and Alertmanager cannot entry and modify information they do not personal.

Create these customers with the useradd command utilizing the --no-create-home and --shell /bin/false flags in order that these customers cannot log into the server:

  • sudo useradd --no-create-home --shell /bin/false blackbox_exporter
  • sudo useradd --no-create-home --shell /bin/false alertmanager

With the customers in place, let’s obtain and configure Blackbox Exporter.

Step 2 — Putting in Blackbox Exporter

First, obtain the newest steady model of Blackbox Exporter to your house listing. You could find the newest binaries together with their checksums on the Prometheus Obtain web page.

  • cd ~
  • curl -LO https://github.com/prometheus/blackbox_exporter/releases/download/v0.12.0/blackbox_exporter-0.12.0.linux-amd64.tar.gz

Earlier than unpacking the archive, confirm the file’s checksums utilizing the next sha256sum command:

  • sha256sum blackbox_exporter-0.12.0.linux-amd64.tar.gz

Evaluate the output from this command with the checksum on the Prometheus obtain web page to make sure that your file is each real and never corrupted:

Output

c5d8ba7d91101524fa7c3f5e17256d467d44d5e1d243e251fd795e0ab4a83605 blackbox_exporter-0.12.0.linux-amd64.tar.gz

If the checksums do not match, take away the downloaded file and repeat the previous steps to re-download the file.

While you’re positive the checksums match, unpack the archive:

  • tar xvf blackbox_exporter-0.12.0.linux-amd64.tar.gz

This creates a listing known as blackbox_exporter-0.12.0.linux-amd64, containing the blackbox_exporter binary file, a license, and instance recordsdata.

Copy the binary file to the /usr/native/bin listing.

  • sudo mv ./blackbox_exporter-0.12.0.linux-amd64/blackbox_exporter /usr/native/bin

Set the consumer and group possession on the binary to the blackbox_exporter consumer, making certain non-root customers cannot modify or change the file:

  • sudo chown blackbox_exporter:blackbox_exporter /usr/native/bin/blackbox_exporter

Lastly, we’ll take away the archive and unpacked listing, as they’re now not wanted.

  • rm -rf ~/blackbox_exporter-0.12.0.linux-amd64.tar.gz ~/blackbox_exporter-0.12.0.linux-amd64

Subsequent, let’s configure Blackbox Exporter to probe endpoints over the HTTP protocol after which run it.

Step 3 — Configuring and Working Blackbox Exporter

Let’s create a configuration file defining how Blackbox Exporter ought to examine endpoints. We’ll additionally create a systemd unit file so we will handle Blackbox’s service utilizing systemd.

We’ll specify the listing of endpoints to probe within the Prometheus configuration within the subsequent step.

First, create the listing for Blackbox Exporter’s configuration. Per Linux conventions, configuration recordsdata go within the /and many others listing, so we’ll use this listing to carry the Blackbox Exporter configuration file as effectively:

  • sudo mkdir /and many others/blackbox_exporter

Then set the possession of this listing to the blackbox_exporter consumer you created in Step 1:

  • sudo chown blackbox_exporter:blackbox_exporter /and many others/blackbox_exporter

Within the newly-created listing, create the blackbox.yml file which can maintain the Blackbox Exporter configuration settings:

  • sudo nano /and many others/blackbox_exporter/blackbox.yml

We’ll configure Blackbox Exporter to make use of the default http prober to probe endpoints. Probers outline how Blackbox Exporter checks if an endpoint is operating. The http prober checks endpoints by sending a HTTP request to the endpoint and testing its response code. You possibly can choose which HTTP technique to make use of for probing, in addition to which standing codes to just accept as profitable responses. Different widespread probers embrace the tcp prober for probing through the TCP protocol, the icmp prober for probing through the ICMP protocol and the dns prober for checking DNS entries.

For this tutorial, we’ll use the http prober to probe the endpoint operating on port 8080 over the HTTP GET technique. By default, the prober assumes that legitimate standing codes within the 2xx vary are legitimate, so we need not present an inventory of legitimate standing codes.

We’ll configure a timeout of 5 seconds, which suggests Blackbox Exporter will wait 5 seconds for the response earlier than reporting a failure. Relying in your software sort, select any worth that matches your wants.

Notice: Blackbox Exporter’s configuration file makes use of the YAML format, which forbids utilizing tabs and strictly requires utilizing two areas for indentation. If the configuration file is formatted incorrectly, Blackbox Exporter will fail to start out up.

Add the next configuration to the file:

/and many others/blackbox_exporter/blackbox.yml

modules:
  http_2xx:
    prober: http
    timeout: 5s
    http:      
      valid_status_codes: []
      technique: GET

You could find extra details about the configuration choices within the the Blackbox Exporter’s documentation.

Save the file and exit your textual content editor.

Earlier than you create the service file, set the consumer and group possession on the configuration file to the blackbox_exporter consumer created in Step 1.

  • sudo chown blackbox_exporter:blackbox_exporter /and many others/blackbox_exporter/blackbox.yml

Now create the service file so you possibly can handle Blackbox Exporter utilizing systemd:

  • sudo nano /and many others/systemd/system/blackbox_exporter.service

Add the next content material to the file:

/and many others/systemd/system/blackbox_exporter.service

[Unit]
Description=Blackbox Exporter
Desires=network-online.goal
After=network-online.goal

[Service]
Consumer=blackbox_exporter
Group=blackbox_exporter
Sort=easy
ExecStart=/usr/native/bin/blackbox_exporter --config.file /and many others/blackbox_exporter/blackbox.yml

[Install]
WantedBy=multi-user.goal

This service file tells systemd to run Blackbox Exporter because the blackbox_exporter consumer with the configuration file situated at /and many others/blackbox_exporter/blackbox.yml. The small print of systemd service recordsdata are past the scope of this tutorial, however if you would like to study extra see the Understanding Systemd Models and Unit Recordsdata tutorial.

Save the file and exit your textual content editor.

Lastly, reload systemd to make use of your newly-created service file:

  • sudo systemctl daemon-reload

Now begin Blackbox Exporter:

  • sudo systemctl begin blackbox_exporter

Ensure it began efficiently by checking the service’s standing:

  • sudo systemctl standing blackbox_exporter

The output accommodates details about Blackbox Exporter’s course of, together with the primary course of identifier (PID), reminiscence use, logs and extra.

Output

● blackbox_exporter.service - Blackbox Exporter Loaded: loaded (/and many others/systemd/system/blackbox_exporter.service; disabled; vendor preset: enabled) Lively: lively (operating) since Thu 2018-04-05 17:48:58 UTC; 5s in the past Important PID: 5869 (blackbox_export) Duties: 4 Reminiscence: 968.0K CPU: 9ms CGroup: /system.slice/blackbox_exporter.service └─5869 /usr/native/bin/blackbox_exporter --config.file /and many others/blackbox_exporter/blackbox.yml

If the service’s standing is not lively (operating), comply with the on-screen logs and retrace the previous steps to resolve the issue earlier than persevering with the tutorial.

Lastly, allow the service to verify Blackbox Exporter will begin when the server restarts:

  • sudo systemctl allow blackbox_exporter

Now that Blackbox Exporter is absolutely configured and operating, we will configure Prometheus to gather metrics about probing requests to our endpoint, so we will create alerts based mostly on these metrics and arrange notifications for alerts utilizing Alertmanager.

Step 4 — Configuring Prometheus To Scrape Blackbox Exporter

As talked about in Step 3, the listing of endpoints to be probed is situated within the Prometheus configuration file as a part of the Blackbox Exporter’s targets directive. On this step you will configure Prometheus to make use of Blackbox Exporter to scrape the Nginx net server operating on port 8080 that you just configured within the prerequisite tutorials.

Open the Prometheus configuration file in your editor:

  • sudo nano /and many others/prometheus/prometheus.yml

At this level, it ought to appear like the next:

/and many others/prometheus/prometheus.yml

world:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'prometheus'
    scrape_interval: 5s
    static_configs:
      - targets: ['localhost:9090']
  - job_name: 'node_exporter'
    scrape_interval: 5s
    static_configs:
      - targets: ['localhost:9100']

On the finish of the scrape_configs directive, add the next entry, which can inform Prometheus to probe the endpoint operating on the native port 8080 utilizing the Blackbox Exporter’s module http_2xx, configured in Step 3.

/and many others/prometheus/prometheus.yml

...
  - job_name: 'blackbox'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
        - http://localhost:8080
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: occasion
      - target_label: __address__
        substitute: localhost:9115

By default, Blackbox Exporter runs on port 9115 with metrics out there on the /probe endpoint.

The scrape_configs configuration for Blackbox Exporter differs from the configuration for different exporters. Probably the most notable distinction is the targets directive, which lists the endpoints being probed as an alternative of the exporter’s handle. The exporter’s handle is specified utilizing the suitable set of __address__ labels.

You will discover a detailed clarification of the relabel directives within the Prometheus documentation.

Your Prometheus configuration file will now appear like this:

Prometheus config file – /and many others/prometheus/prometheus.yml

world:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'prometheus'
    scrape_interval: 5s
    static_configs:
      - targets: ['localhost:9090']
  - job_name: 'node_exporter'
    scrape_interval: 5s
    static_configs:
      - targets: ['localhost:9100']
  - job_name: 'blackbox'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
        - http://localhost:8080
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: occasion
      - target_label: __address__
        substitute: localhost:9115

Save the file and shut your textual content editor.

Restart Prometheus to place the modifications into impact:

  • sudo systemctl restart prometheus

Ensure it is operating as anticipated by checking the Prometheus service standing:

  • sudo systemctl standing prometheus

If the service’s standing is not lively (operating), comply with the on-screen logs and retrace the previous steps to resolve the issue earlier than persevering with the tutorial.

At this level, you’ve got configured Prometheus to scrape metrics from Blackbox Exporter. With the intention to obtain alerts from Alertmanager, within the subsequent step you will create an acceptable set of Prometheus alert guidelines.

Step 5 — Creating Alert Guidelines

Prometheus Alerting is separated into two elements. The primary half is dealt with by the Prometheus server and consists of producing alerts based mostly on alert guidelines and sending them to Alertmanager. The second half is finished by Alertmanager, which manages obtained alerts and sends them to the suitable receivers, relying on the configuration.

On this step, you will study the fundamental syntax of alert guidelines as you create an alert rule to examine in case your server is out there.

First, create a file to retailer your alerts. Create an empty file named alert.guidelines.yml within the /and many others/prometheus listing:

  • sudo contact /and many others/prometheus/alert.guidelines.yml

As this file is a part of the Prometheus configuration, make sure that the possession is about to the prometheus consumer you created within the prerequisite Prometheus tutorial:

  • sudo chown prometheus:prometheus /and many others/prometheus/alert.guidelines.yml

With the alerts file in place, we have to inform Prometheus about it by including the suitable directive to the configuration file.

Open the Prometheus configuration file in your editor:

  • sudo nano /and many others/prometheus/prometheus.yml

Add the rule_files directive after the world directive to make Prometheus load your newly-created alerts file when Prometheus begins.

/and many others/prometheus/prometheus.yml

world:
  scrape_interval: 15s

rule_files:
  - alert.guidelines.yml

scrape_configs:
...

Save the file and exit your textual content editor.

Now let’s construct a rule that checks if the endpoint is down.

With the intention to make the alert rule, you will use Blackbox Exporter’s probe_success metric which returns 1 if the endpoint is up and 0 if it is not.

The probe_success metric accommodates two labels: the occasion label with the handle of the endpoint, and the job label with the identify of the exporter that collected the metric.

Open the alert guidelines file in your editor:

  • sudo nano /and many others/prometheus/alert.guidelines.yml

Just like the Prometheus configuration file, the alerts rule file makes use of the YAML format, which strictly forbids tabs and requires two areas for indentation. Prometheus will fail to start out if the file is incorrectly formatted.

First, we’ll create an alert rule known as EndpointDown to examine if the probe_sucess metric equals 0 with a length of 10 seconds. This ensures that Prometheus won’t ship any alert if the endpoint is just not out there for lower than 10 seconds. You are free to decide on no matter length you need relying in your software sort and desires.

Additionally, we’ll connect two labels denoting essential severity and a abstract of the alert, so we will simply handle and filter alerts.

If you wish to embrace extra particulars within the alert’s labels and annotations, you should utilize the {{ $labels.metrics_label }} syntax to get the label’s worth. We’ll use this to incorporate the endpoint’s handle from the metric’s occasion label.

Add the next rule to the alerts file:

/and many others/prometheus/alert.guidelines.yml

teams:
- identify: alert.guidelines
  guidelines:
  - alert: EndpointDown
    expr: probe_success == 0
    for: 10s
    labels:
      severity: "critical"
    annotations:
      abstract: "Endpoint {{ $labels.instance }} down"

Save the file and exit your textual content editor.

Earlier than restarting Prometheus, make sure that your alerts file is syntactically appropriate utilizing the next promtool command:

  • sudo promtool examine guidelines /and many others/prometheus/alert.guidelines.yml

The output accommodates the variety of guidelines discovered within the file, together with details about whether or not or not the foundations are syntactically appropriate:

Output

Checking /and many others/prometheus/alert.guidelines.yml SUCCESS: 1 guidelines discovered

Lastly, restart Prometheus to use the modifications:

  • sudo systemctl restart prometheus

Confirm the service is operating with the standing command:

  • sudo systemctl standing prometheus

If the service’s standing is not lively, comply with the on-screen logs and retrace the previous steps to resolve the issue earlier than persevering with the tutorial.

With the alert guidelines in place, we will obtain and set up Alertmanager.

Step 6 — Downloading Alertmanager

Blackbox Exporter is configured and our alert guidelines are in place. Let’s obtain and set up Alertmanager to course of the alerts obtained by Prometheus.

You could find the newest binaries together with their checksums on the Prometheus obtain web page. Obtain and unpack the present steady model of Alertmanager into your house listing:

  • cd ~
  • curl -LO https://github.com/prometheus/alertmanager/releases/download/v0.14.0/alertmanager-0.14.0.linux-amd64.tar.gz

Earlier than unpacking the archive, confirm the file’s checksums utilizing the next sha256sum command:

  • sha256sum alertmanager-0.14.0.linux-amd64.tar.gz

Evaluate the output from this command with the checksum on the Prometheus obtain web page to make sure that your file is each real and never corrupted.

Output

caddbbbe3ef8545c6cefb32f9a11207ae18dcc788e8d0fb19659d88c58d14b37 alertmanager-0.14.0.linux-amd64.tar.gz

If the checksums do not match, take away the downloaded file and repeat the previous steps to re-download the file.

As soon as you’ve got verified the obtain, unpack the archive:

  • tar xvf alertmanager-0.14.0.linux-amd64.tar.gz

This creates a listing known as alertmanager-0.14.0.linux-amd64 containing two binary recordsdata (alertmanager and amtool), a license and an instance configuration file.

Transfer the 2 binary recordsdata to the /usr/native/bin listing:

  • sudo mv alertmanager-0.14.0.linux-amd64/alertmanager /usr/native/bin
  • sudo mv alertmanager-0.14.0.linux-amd64/amtool /usr/native/bin

Set the consumer and group possession on the binary recordsdata to the alertmanager consumer you created in Step 1:

  • sudo chown alertmanager:alertmanager /usr/native/bin/alertmanager
  • sudo chown alertmanager:alertmanager /usr/native/bin/amtool

Take away the leftover recordsdata from your house listing as they’re now not wanted:

  • rm -rf alertmanager-0.14.0.linux-amd64 alertmanager-0.14.0.linux-amd64.tar.gz

Now that the required recordsdata are within the acceptable location, we will configure Alertmanager to ship notifications for alerts over electronic mail.

Step 7 — Configuring Alertmanager To Ship Alerts Over E mail

On this step, you will create the listing and recordsdata to retailer Alertmanager’s information and configuration settings, after which configure Alertmanager to ship alerts through electronic mail.

Following the usual Linux conventions, we’ll create a listing in /and many others to retailer Alertmanager’s configuration file.

  • sudo mkdir /and many others/alertmanager

Set the consumer and group possession for the newly-created listing to the alertmanager consumer:

  • sudo chown alertmanager:alertmanager /and many others/alertmanager

We’ll retailer the configuration file within the alertmanager.yml file, so create this file and open it in your editor:

  • sudo nano /and many others/alertmanager/alertmanager.yml

Like different Prometheus-related recordsdata, this one makes use of YAML format as effectively, so make sure that to make use of two areas as an alternative of tabs for indentation.

We’ll configure Alertmanager to ship emails utilizing Postfix, which you put in following the prerequisite tutorial. We have to present the SMTP server’s handle, utilizing the smtp_smarthost directive, in addition to the handle we need to ship emails from, utilizing the smtp_from directive. As Postfix is operating on the identical server as Alertmanager, the server’s handle is localhost:25. We’ll use the alertmanager consumer for sending emails.

By default, Postfix would not have TLS configured, so we have to inform Alertmanager to permit non-TLS SMTP servers utilizing the smtp_require_tls directive.

Put the SMTP configuration below the world directive, because it’s used to specify parameters legitimate in all different configuration contexts. This consists of SMTP configuration in our case, and can even embrace API tokens for numerous integrations:

Alertmanager config file half 1 – /and many others/alertmanager/alertmanager.yml

world:
  smtp_smarthost: 'localhost:25'
  smtp_from: '[email protected]your_domain'
  smtp_require_tls: false

Notice: Ensure to switch your_domin within the smtp_from directive along with your area identify.

At this level, Alertmanager is aware of tips on how to ship emails, however we have to outline the way it will deal with incoming alerts utilizing the route directive. The route directive is utilized to each incoming alert and defines properties equivalent to how Alertmanager will group alerts, who’s the default recipient, or how lengthy Alertmanager will wait earlier than sending an preliminary alert.

To group alerts, use the group_by sub-directive, which takes an inline array of labels (equivalent to ['label-1', 'label-2']). Grouping ensures that alerts containing the identical labels will likely be grouped and despatched in the identical batch.

Each route directive has a single receiver outlined utilizing the receiver sub-directive. If you wish to add a number of receivers, you will must both outline a number of receivers below the identical directive or nest a number of route directives utilizing the routes sub-directive. On this tutorial, we’ll cowl the primary strategy to configure Slack alerts.

On this case, we’ll solely group by Blackbox’s occasion label and the severity label we connected to the alert in step 6, making certain we’ll get a number of alerts for our endpoint with essential severity in a single mail.

Add the next group_by directive:

Alertmanager config file half 2 – /and many others/alertmanager/alertmanager.yml

...
route:
  group_by: ['instance', 'alert']

Subsequent, we’ll outline intervals, equivalent to how lengthy Alertmanager will wait earlier than sending preliminary and new alerts.

Utilizing the group_wait sub-directive, we’ll outline how lengthy Alertmanager will wait earlier than sending the preliminary alert. Throughout this era, Alertmanager will watch for Prometheus to ship different alerts in the event that they exist to allow them to be despatched in the identical batch. As we solely have one alert, we’ll choose an arbitrary worth of 30 seconds.

Subsequent, utilizing the group_interval interval, we’ll outline how lengthy Alertmanager will wait earlier than sending the subsequent batch of alerts if there are new alerts in the identical group. You are free to decide on any worth relying in your wants, however we’ll set this to each 5 minutes.

The final interval we’ll configure is the repeat_interval, which defines how lengthy Alertmanager will wait earlier than it sends notification if alerts usually are not resolved but. You possibly can select no matter worth fits your wants, however we’ll use the arbitrary worth of three hours.

Lastly, utilizing the receiver sub-directive, outline who will obtain notifications for the alerts. We’ll use a receiver known as team-1, which we’ll outline later.

Modify the route directive so it appears like this:

Alertmanager config file half 2 – /and many others/alertmanager/alertmanager.yml

route:
  group_by: ['instance', 'severity']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 3h
  receiver: team-1

If you wish to match and ship notifications solely about particular alerts, you should utilize the match and match_re sub-directives to filter out alerts by their label’s worth. The match sub-directive represents equality match, the place the match_re sub-directive represents matching through common expressions.

Now we’ll configure the team-1 receiver so you possibly can obtain notifications for alerts. Beneath the receivers directive you possibly can outline receivers containing the identify and acceptable configuration sub-directive. The listing of accessible receivers and directions on tips on how to configure them is out there because the a part of Alertmanager’s documentation.

With the intention to configure the team-1 electronic mail receiver, we’ll use the email_configs sub-directive below the receivers directive:

Alertmanager config file half 3 – /and many others/alertmanager/alertmanager.yml

receivers:
  - identify: 'team-1'
    email_configs:
      - to: 'your-email-address'

At this level, you will have configured Alertmanager to ship notifications for alerts to your e-mail handle. Your configuration file ought to appear like:

Alertmanager config file – /and many others/alertmanager/alertmanager.yml

world:
  smtp_smarthost: 'localhost:25'
  smtp_from: '[email protected]instance.com'
  smtp_require_tls: false

route:
  group_by: ['instance', 'severity']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 3h
  receiver: team-1

receivers:
  - identify: 'team-1'
    email_configs:
      - to: 'your-email-address'

Within the subsequent step, we’ll configure Alertmanager to ship alerts to your Slack channel. In case you do not need to configure Slack, you possibly can skip straight to step 10 the place we’ll create the service file and configure Prometheus to work with Alertmanager.

Step 8 — Configuring Alertmanager To Ship Alerts Over Slack

Earlier than continuing with this step, ensure you have created an Slack account and that you’ve got a Slack workspace out there.

To ship alerts to Slack, first create an Incoming Webhook.

Level your browser to the Incoming Webhook creation web page out there at https://workspace-name.slack.com/companies/new/incoming-webhook/. You will get the web page containing particulars about Incoming Webhooks in addition to a dropdown from which it’s essential select the channel the place you need to ship alerts.

Slack Incoming Webhook

When you select the channel, click on on the Add Incoming WebHooks integration button.

You will see a brand new web page confirming that the webhook was created efficiently. Copy the Webhook URL displayed on this web page, as you will use it to configure Alertmanager’s Slack notifications.

Open the Alertmanager configuration file in your editor to configure Slack notifications:

  • sudo nano /and many others/alertmanager/alertmanager.yml

First, add the slack_api_url sub-directive to the world a part of your configuration, utilizing the URL you bought whenever you created the Slack Incoming Webhook.

Alertmanager config file half 1 – /and many others/alertmanager/alertmanager.yml

world:
  smtp_smarthost: 'localhost:25'
  smtp_from: '[email protected]instance.com'
  smtp_require_tls: false

  slack_api_url: 'your_slack_webhook_url'

There are two methods to ship alerts to a number of receivers:

  1. Embrace a number of receiver configurations below the identical entry. That is the the least error-prone resolution and the best technique.
  2. Create a number of receiver entries and nest a number of route directives.

We can’t cowl the second strategy on this tutorial, however when you’re , check out the Route configuration portion of Alertmanager documentation.

Within the team-1 receiver, add a brand new sub-directive known as slack_configs and supply the identify of the channel that ought to obtain alerts. On this case, we’ll use use the common channel:

Alertmanager config file half 2 – /and many others/alertmanager/alertmanager.yml

receivers:
  - identify: 'team-1'
    email_configs:
      - to: 'your-email-address'
    slack_configs:
      - channel: 'common<^>'

Your accomplished configuration file will appear like the next:

Alertmanager config file – /and many others/alertmanager/alertmanager.yml

world:
  smtp_smarthost: 'localhost:25'
  smtp_from: '[email protected]instance.com'
  smtp_require_tls: false

  slack_api_url: 'your_slack_webhook_url'

route:
  group_by: ['instance', 'severity']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 3h
  receiver: team-1

receivers:
  - identify: 'team-1'
    email_configs:
      - to: 'your-email-address'
    slack_configs:
      - channel: 'common'

Save the file and exit your editor.

We’re now able to run Alertmanager for the primary time.

Step 9 — Working Alertmanager

Let’s get Alertmanager up and operating. We’ll first create a systemd unit file for Alertmanager to handle its service utilizing systemd. Then we’ll replace Prometheus to make use of Alertmanager.

Create a brand new systemd unit file and open it in your textual content editor:

  • sudo nano /and many others/systemd/system/alertmanager.service

Add the next to the file to configure systemd to run Alertmanager because the alertmanager consumer, utilizing the configuration file situated at /and many others/alertmanager/alertmanager.yml and Alertmanager’s URL, configured to make use of your server’s IP handle:

/and many others/systemd/system/alertmanager.service

[Unit]
Description=Alertmanager
Desires=network-online.goal
After=network-online.goal

[Service]
Consumer=alertmanager
Group=alertmanager
Sort=easy
WorkingDirectory=/and many others/alertmanager/
ExecStart=/usr/native/bin/alertmanager --config.file=/and many others/alertmanager/alertmanager.yml --web.external-url http://your_server_ip:9093

[Install]
WantedBy=multi-user.goal

This can run Alertmanager because the alertmanager consumer. It additionally tells Alertmanager to make use of the URL http://your_server_ip:9093 for its Web UI, the place 9093 is Alertmanager’s default port. Make sure you embrace the protocol (http://) or issues will not work.

Save the file and shut your textual content editor.

Subsequent, we have to inform Prometheus about Alertmanager by including the suitable Alertmanager service discovery listing to the Prometheus configuration file. By default, Alertmanager is operating on port 9093, and because it’s on the identical server as Prometheus, we’ll use the handle localhost:9093.

Open the Prometheus configuration file:

  • sudo nano /and many others/prometheus/prometheus.yml

After the rule_files directive, add the next alerting directive:

Prometheus configuration file – /and many others/prometheus/prometheus.yml

...
rule_files:
  - alert.guidelines.yml

alerting:
  alertmanagers:
  - static_configs:
    - targets:
      - localhost:9093
...

When you’re performed, save the file and shut your textual content editor.

So as to have the ability to comply with URLs from the alerts you obtain, it’s essential inform Prometheus the IP handle or area identify of your server utilizing the -web.external-url flag whenever you begin Prometheus.

Open the systemd unit file for Prometheus:

  • sudo nano /and many others/systemd/system/prometheus.service

Substitute the prevailing ExecStart line with the next one:

ExecStart=/usr/native/bin/prometheus --config.file /and many others/prometheus/prometheus.yml 
    --storage.tsdb.path /var/lib/prometheus/ --web.console.templates=/and many others/prometheus/consoles 
    --web.console.libraries=/and many others/prometheus/console_libraries  
    --web.external-url http://your_server_ip

Your new Prometheus unit file will appear like this:

Prometheus service file – /and many others/systemd/system/prometheus.service

[Unit]
Description=Prometheus
Desires=network-online.goal
After=network-online.goal

[Service]
Consumer=prometheus
Group=prometheus
Sort=easy
ExecStart=/usr/native/bin/prometheus --config.file /and many others/prometheus/prometheus.yml 
    --storage.tsdb.path /var/lib/prometheus/ --web.console.templates=/and many others/prometheus/consoles 
    --web.console.libraries=/and many others/prometheus/console_libraries  
    --web.external-url http://your_server_ip

[Install]
WantedBy=multi-user.goal

Save the file and shut your textual content editor.

Reload systemd and restart Prometheus to use the modifications:

  • sudo systemctl daemon-reload
  • sudo systemctl restart prometheus

Ensure Prometheus is working as supposed by checking the service’s standing:

  • sudo systemctl standing prometheus

If the service’s standing is not lively (operating), comply with the on-screen logs and retrace the previous steps to resolve the issue earlier than persevering with the tutorial.

Lastly, begin Alertmanager for the primary time:

  • sudo systemctl begin alertmanager

Examine the service’s standing to verify Alertmanager is working as supposed:

  • sudo systemctl standing alertmanager

If the service’s standing is not lively (operating), comply with the on-screen messages and retrace the previous steps to resolve the issue earlier than persevering with the tutorial.

Lastly, allow the service to verify Alertmanager will begin when the system boots:

  • sudo systemctl allow alertmanager

To entry Alertmanager’s Web UI, enable site visitors to port 9093 by way of your firewall:

Alertmanager is now configured to ship notifications for alerts through electronic mail and Slack. Let's guarantee it really works.

Step 10 — Testing Alertmanager

Let's make sure that Alertmanger is working appropriately and sending emails and Slack notifications. We'll disable the endpoint by eradicating the Nginx server block you created within the prerequisite tutorials:

  • sudo rm /and many others/nginx/sites-enabled/your_domain

Reload Nginx to use the modifications:

  • sudo systemctl reload nginx

If you wish to affirm it is truly disabled, you possibly can level your net browser to your server's handle. It is best to see a message indicating that the location is now not reachable. In case you do not, retrace the previous steps and ensure you deleted appropriate server block and reloaded Nginx.

Relying on the group_wait interval, which is 30 seconds in our case, you must obtain electronic mail and Slack notifications after 30 seconds.

In case you do not, examine the service's standing by utilizing the next standing instructions and comply with the on-screen logs to seek out the reason for the issue:

  • sudo systemctl standing alertmanager
  • sudo systemctl standing prometheus

You too can examine the alert's standing from the Prometheus Web UI, by pointing your net browser to the http://your_server_ip/alerts. You will be requested to enter the username and password you selected by following the Prometheus tutorial. By clicking on the alert identify, you will see the standing, the alert rule, and related labels:

Prometheus UI - alerts

As soon as you've got verified Alertmanager is working, allow the endpoint by re-creating the symbolic hyperlink from the sites-available listing to the sites-enabled listing:

  • sudo ln -s /and many others/nginx/sites-available/your_domain /and many others/nginx/sites-enabled

Reload Nginx as soon as once more to use the modifications:

  • sudo systemctl reload nginx

Within the subsequent step, we'll take a look at tips on how to use Alertmanager's Command-Line Interface.

Step 11 — Managing Alerts Utilizing the CLI

Alertmanager comes with the command-line instrument amtool, which helps you to monitor, handle and silence alerts.

The amtool instrument requires you to offer the URL of Alertmanager utilizing the --alertmanager.url flag each time you execute an command. With the intention to use amtool with out offering the URL, we'll begin by making a configuration file.

Default places for the configuration file are $HOME/.config/amtool/config.yml, which makes the configuration out there solely in your present consumer, and /and many others/amtool/config.yml, which makes the configuration out there for the each consumer on the server.

You are free to decide on no matter fits your wants, however for this tutorial, we'll use the $HOME/.config/amtool/config.yml file.

First, create the listing. The -p flag tells mkdir to create any crucial mother or father directories alongside the way in which:

  • mkdir -p $HOME/.config/amtool

Create the config.yml file and open it in your textual content editor:

  • nano $HOME/.config/amtool/config.yml

Add the next line to inform amtool to make use of Alertmanager with the http://localhost:9093 URL:

~/.config/amtool/config.yml

alertmanager.url: http://localhost:9093

Save the file and exit your textual content editor.

Now, we'll check out what we will do with the amtool command line instrument.

Utilizing the amtool alert question command, you possibly can listing all alerts which have been ship to Alertmanager:

The output exhibits the alert's identify, the time of the alert's first incidence, and the alert's abstract you supplied whenever you configured it:

Output

Alertname Begins At Abstract EndpointDown 2018-04-03 08:48:47 UTC Endpoint http://localhost:8080 down

You too can filter alerts by their labels utilizing the suitable matcher. A matcher accommodates the label identify, the suitable operation, which could be = for full matching and =~ for partial matching, and the label's worth.

If you wish to listing all alerts which have a essential severity label connected, use the severity=essential matcher within the alert question command:

  • amtool alert question severity=essential

Like earlier than, the output accommodates the alert's identify, the time of alert's first incidence and the alert's abstract.

Output

Alertname Begins At Abstract EndpointDown 2018-04-03 08:48:47 UTC Endpoint http://localhost:8080 down

You need to use common expressions to match labels with the =~ operator. For instance, to listing all alerts for http://localhost endpoints not relying on the port, you should utilize the occasion=~http://localhost.* matcher:

  • amtool alert question occasion=~http://localhost.*

As you will have just one alert and endpoint, the output could be the identical as within the earlier instance.

To have a look at the Alertmanager configuration, use the amtool config command:

The output will include the content material of the /and many others/alertmanager/alertmanager.yml file.

Now let us take a look at tips on how to silence alerts utilizing amtool.

Silencing alerts permits you to mute alerts based mostly on the matcher for a given time. Throughout that interval, you will not obtain any electronic mail or Slack notification for the silenced alert.

The amtool silence add command takes the matcher as an argument and creates a brand new silence based mostly on the matcher.

To outline the expiration of an alert, use the --expires flag with desired length of the silence, equivalent to 1h or the --expire-on flag with the time of silence expiration within the RFC3339 format. For instance, the format 2018-10-04T07:50:00+00:00 represents 07.50am on October 4th, 2018.

If the --expires or the --expires-on flag is just not supplied, alerts will likely be silenced for 1 hour.

To silence all alerts for the http://localhost:8080 occasion for Three hours, you'd use the next command:

  • amtool silence add occasion=http://localhost:8080 --expires 3h

The output accommodates an identification quantity for the silence, so make sure that to notice it down as you will want it in case you need to take away the silence:

Output

4e89b15b-0814-41d3-8b74-16c513611732

If you wish to present extra info when creating the silence, such because the creator and feedback, use the --author and --comment flags:

  • amtool silence add severity=essential --expires 3h --author "Sammy The Shark" --comment "Investigating the progress"

Like earlier than, the output accommodates the ID of the silence:

Output

12b7b9e1-f48a-4ceb-bd85-65ac882ceed1

The command amtool silence question will present the listing of all non-expired silences:

The output accommodates the ID of the silence, the listing of matchers, the expiration timestamp, the creator, and a remark:

Output

ID Matchers Ends At Created By Remark 12b7b9e1-f48a-4ceb-bd85-65ac882ceed1 severity=essential 2018-04-04 08:02:58 UTC Sammy The Shark Investigating within the progress 4e89b15b-0814-41d3-8b74-16c513611732 occasion=http://localhost:8080 2018-04-04 08:14:21 UTC sammy

Much like the alert question command, you should utilize label matchers to filter the output by labels connected on creation:

  • amtool silence question occasion=http://localhost:8080

Like earlier than, the output will embrace the ID quantity and particulars of the alert:

Output

ID Matchers Ends At Created By Remark 4e89b15b-0814-41d3-8b74-16c513611732 occasion=http://localhost:8080 2018-04-04 08:14:21 UTC sammy

Lastly, to run out a silence, use the amtool silence expire with the ID of the silence you need to expire:

  • amtool silence expire 12b7b9e1-f48a-4ceb-bd85-65ac882ceed1
  • amtool silence expire 4e89b15b-0814-41d3-8b74-16c513611732

No output represents profitable command execution. In case you see an error, ensure you supplied the right ID of the silence.

Conclusion

On this tutorial you configured Blackbox Exporter and Alertmanager to work along with Prometheus so you possibly can obtain alerts through electronic mail and Slack. You additionally used Alertmanager's command-line interface, amtool, to handle and silence alerts.

If you would like to study extra about different Alertmanager integrations, check out the [Configuration]((https://prometheus.io/docs/alerting/configuration/)) portion of Alertmanager's documentation.

Additionally, you possibly can have a look tips on how to combine Prometheus Alerts with different companies equivalent to Grafana.

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