Tutorial to run Promtail on AWS EC2 (#2321)

* Starting the work with spining out an ec2 instance. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * Adds a tutorial on how to run Promtail on AWS EC2. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * Improve gist link. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * More adjustements. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * Update docs/clients/aws/ec2/ec2.md * Update docs/clients/aws/ec2/ec2.md Co-authored-by: Ed Welch <ed@oqqer.com> * Move off curl gist to grafana/loki repo. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * Add systemd as most user will need it. Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> * yupo Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com> Co-authored-by: Ed Welch <ed@oqqer.com>
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+# Running Promtail on AWS EC2
+
+In this tutorial we're going to setup [Promtail][promtail] on an AWS EC2 instance and configure it to sends all its logs to a Loki instance.
+
+<!-- TOC -->
+
+- [Running Promtail on AWS EC2](#running-promtail-on-aws-ec2)
+    - [Requirements](#requirements)
+    - [Creating an EC2 instance](#creating-an-ec2-instance)
+    - [Setting up Promtail](#setting-up-promtail)
+    - [Configuring Promtail as a service](#configuring-promtail-as-a-service)
+    - [Sending systemd logs](#sending-systemd-logs)
+
+<!-- /TOC -->
+
+## Requirements
+
+Before we start you'll need:
+
+- An AWS account (with the `AWS_ACCESS_KEY` and `AWS_SECRET_KEY`)
+- A VPC that is routable from the internet. (Follow those [instructions][create an vpc] if you need to create one)
+- A SSH public key. (Follow those [instructions][create an ssh key] if you need a new one)
+- The [AWS CLI][aws cli] configured (run `aws configure`).
+- A Grafana instance with a Loki data source already configured, you can use [GrafanaCloud][GrafanaCloud] free trial.
+
+For the sake of simplicity we'll use a GrafanaCloud Loki and Grafana instances, you can get an free account for this tutorial on our [website][GrafanaCloud], but all the steps are the same if you're running your own Open Source version of Loki and Grafana instances.
+
+To make it easy to learn all the following instructions are manual, however in a real setup we recommend you to use provisioning tools such as [Terraform][terraform], [CloudFormation][cloud formation], [Ansible][ansible] or [Chef][chef].
+
+## Creating an EC2 instance
+
+As a first step we're going to import our SSH key to AWS so that we can SSH to our future EC2 instance, let's run our first command:
+
+```bash
+aws ec2 import-key-pair --key-name "promtail-ec2" --public-key-material fileb://~/.ssh/id_rsa.pub
+```
+
+Next we're going to create a [security group][security group], make sure to note the group id, we'll need it for the following command:
+
+```bash
+aws ec2 create-security-group --group-name promtail-ec2  --description "promtail on ec2" --vpc-id vpc-668d120f
+{
+    "GroupId": "sg-02c489bbdeffdca1d"
+}
+```
+
+Now let's authorize inbound access for SSH and [Promtail][promtail] server:
+
+```bash
+aws ec2 authorize-security-group-ingress --group-id sg-02c489bbdeffdca1d --protocol tcp --port 22 --cidr 0.0.0.0/0
+aws ec2 authorize-security-group-ingress --group-id sg-02c489bbdeffdca1d --protocol tcp --port 3100 --cidr 0.0.0.0/0
+```
+
+> You don't need to open those ports to all IPs as shown above you can use your own IP range.
+
+We're going to create an [Amazon Linux 2][Amazon Linux 2] instance as this is one of the most popular but feel free to use the AMI of your choice.
+
+To create the instance use the following command, make sure to note the instance id:
+
+```bash
+aws ec2 run-instances --image-id ami-016b213e65284e9c9 --count 1 --instance-type t2.micro --key-name promtail-ec2 --security-groups promtail-ec2
+```
+
+To make it more interesting later let's tag (`Name=promtail-demo`) our instance:
+
+```bash
+aws ec2 create-tags --resources i-041b0be05c2d5cfad --tags Key=Name,Value=promtail-demo
+```
+
+> Tags enable you to categorize your AWS resources in different ways, for example, by purpose, owner, or environment. This is useful when you have many resources of the same type—you can quickly identify a specific resource based on the tags that you've assigned to it. You'll see later, Promtail can transform those tags into [Loki labels][labels].
+
+Finally let's grab the public DNS of our instance:
+
+```bash
+aws ec2 describe-instances --filters "Name=tag:Name,Values=promtail-demo" --query "Reservations[].Instances[].NetworkInterfaces[].Association.PublicDnsName"
+```
+
+and start an SSH session:
+
+```bash
+ssh ec2-user@ec2-13-59-62-37.us-east-2.compute.amazonaws.com
+```
+
+## Setting up Promtail
+
+First let's make sure we're running as root by using `sudo -s`.
+Next we'll download, install and give executable right to [Promtail][promtail].
+
+```bash
+mkdir /opt/promtail && cd /opt/promtail
+curl -O -L "https://github.com/grafana/loki/releases/download/v1.5.0/promtail-linux-amd64.zip"
+unzip "promtail-linux-amd64.zip"
+chmod a+x "promtail-linux-amd64"
+```
+
+Now we're going to download the [promtail configuration][promtail configuration] file below and edit it, don't worry we will explain what those means.
+The file is also available on [github][config gist].
+
+```bash
+curl https://raw.githubusercontent.com/grafana/loki/master/docs/clients/aws/ec2/promtail-ec2.yaml > ec2-promtail.yaml
+vi ec2-promtail.yaml
+```
+
+```yaml
+server:
+  http_listen_port: 3100
+  grpc_listen_port: 0
+
+clients:
+  - url: https://<user id>:<api secret>@logs-prod-us-central1.grafana.net/loki/api/v1/push
+
+positions:
+  filename: /opt/promtail/positions.yaml
+
+scrape_configs:
+  - job_name: ec2-logs
+    ec2_sd_configs:
+      - region: us-east-2
+        access_key: REDACTED
+        secret_key: REDACTED
+    relabel_configs:
+      - source_labels: [__meta_ec2_tag_Name]
+        target_label: name
+        action: replace
+      - source_labels: [__meta_ec2_instance_id]
+        target_label: instance
+        action: replace
+      - source_labels: [__meta_ec2_availability_zone]
+        target_label: zone
+        action: replace
+      - action: replace
+        replacement: /var/log/**.log
+        target_label: __path__
+      - source_labels: [__meta_ec2_private_dns_name]
+        regex: "(.*)"
+        target_label: __host__
+```
+
+The **server** section indicates promtail to bind his http server to 3100. Promtail serves HTTP pages for [troubleshooting][troubleshooting loki] service discovery and targets.
+
+The **clients** section allow you to target your loki instance, if you're using GrafanaCloud simply replace `<user id>` and `<api secret>` with your credentials. Otherwise just replace the whole URL with your custom Loki instance.(e.g `http://my-loki-instance.my-org.com/loki/api/v1/push`)
+
+[Promtail][promtail] uses the same [Prometheus **scrape_configs**][prometheus scrape config]. This means if you already own a Prometheus instance the config will be very similar and easy to grasp.
+
+Since we're running on AWS EC2 we want to uses EC2 service discovery, this will allows us to scrape metadata about the current instance (and even your custom tags) and attach those to our logs. This way managing and querying on logs will be much easier.
+
+Make sure to replace accordingly you current `region`, `access_key` and `secret_key`, alternatively you can use an [AWS Role][role] ARN, for more information about this, see the `ec2_sd_config` [documentation][ec2_sd_config].
+
+Finally the [`relabeling_configs`][relabel] section has three purposes:
+
+1. Selecting the labels discovered you want to attach to your targets. In our case here, we're keeping `instance_id` as instance, the tag `Name` as name and the `zone` of the instance. Make sure to check out the Prometheus [documentation][ec2_sd_config] for the full list of available labels.
+
+2. Choosing where promtail should find log files to tail, in our example we want to include all log files that exist in `/var/log` using the glob `/var/log/**.log`. If you need to use multiple glob, you can simply add another job in your `scrape_configs`.
+
+3. Ensuring discovered targets are only for the machine Promtail currently runs on. This is achieve by adding the label `__host__` using the incoming metadata `__meta_ec2_private_dns_name`. If it doesn't match the current `HOSTNAME` environnement variable, the target will be dropped.
+
+Alright we should be ready to fire up promtail, we're going to run it using the flag `--dry-run`. This is perfect to ensure everything is correctly, specially when you're still playing around with the configuration. Don't worry when using this mode, Promtail won't send any logs and won't remember any file positions.
+
+```bash
+ ./promtail-linux-amd64 -config.file=./ec2-promtail.yaml --dry-run
+```
+
+If everything is going well Promtail should print out log lines with their labels discovered instead of sending them to Loki, like shown below:
+
+```bash
+2020-07-08T14:51:38	{filename="/var/log/cloud-init.log", instance="i-041b0be05c2d5cfad", name="promtail-demo", zone="us-east-2c"}	Jul 07 21:37:24 cloud-init[3035]: util.py[DEBUG]: loaded blob returned None, returning default.
+```
+
+Don't hesitate to edit the your config file and start Promtail again to try your config out.
+
+If you want to see existing targets and available labels you can reach promtail server using the public dns assigned to your instance:
+
+```bash
+open http://ec2-13-59-62-37.us-east-2.compute.amazonaws.com:3100/
+```
+
+For example the page below is the service discovery page. It shows you all discovered targets, with their respective available labels and the reason it was dropped if it was the case.
+
+![discovery page page][discovery page]
+
+This page is really useful to understand what labels are available to forward with the `relabeling` configuration but also why Promtail is not scraping your target.
+
+## Configuring Promtail as a service
+
+Now that we have correctly configured Promtail. We usually want to make sure it runs as a [systemd service][systemd], so it can automatically restart on failure or when the instance restart.
+
+Let's create a new service using `vim /etc/systemd/system/promtail.service` and copy the service definition below:
+
+```systemd
+[Unit]
+Description=Promtail
+
+[Service]
+User=root
+WorkingDirectory=/opt/promtail/
+ExecStartPre=/bin/sleep 30
+ExecStart=/opt/promtail/promtail-linux-amd64 --config.file=./ec2-promtail.yaml
+SuccessExitStatus=143
+TimeoutStopSec=10
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+```
+
+Let's reload the systemd, enable then start the promtail service:
+
+```bash
+systemctl daemon-reload
+systemctl enable promtail.service
+systemctl start promtail.service
+```
+
+You can verify that the service run correctly using the following command:
+
+```bash
+systemctl status promtail.service -l
+
+● promtail.service - Promtail
+   Loaded: loaded (/etc/systemd/system/promtail.service; enabled; vendor preset: disabled)
+   Active: active (running) since Wed 2020-07-08 15:48:57 UTC; 4s ago
+ Main PID: 2732 (promtail-linux-)
+   CGroup: /system.slice/promtail.service
+           └─2732 /opt/promtail/promtail-linux-amd64 --config.file=./ec2-promtail.yaml
+
+Jul 08 15:48:57 ip-172-31-45-69.us-east-2.compute.internal systemd[1]: Started Promtail.
+Jul 08 15:48:57 ip-172-31-45-69.us-east-2.compute.internal systemd[1]: Starting Promtail...
+Jul 08 15:48:57 ip-172-31-45-69.us-east-2.compute.internal promtail-linux-amd64[2732]: level=warn ts=2020-07-08T15:48:57.559085451Z caller=filetargetmanager.go:98 msg="WARNING!!! entry_parser config is deprecated, please change to pipeline_stages"
+Jul 08 15:48:57 ip-172-31-45-69.us-east-2.compute.internal promtail-linux-amd64[2732]: level=info ts=2020-07-08T15:48:57.559869071Z caller=server.go:179 http=[::]:3100 grpc=[::]:35127 msg="server listening on addresses"
+Jul 08 15:48:57 ip-172-31-45-69.us-east-2.compute.internal promtail-linux-amd64[2732]: level=info ts=2020-07-08T15:48:57.56029474Z caller=main.go:67 msg="Starting Promtail" version="(version=1.5.0, branch=HEAD, revision=12c7eab8)"
+```
+
+You can now verify in Grafana that Loki has correctly received your instance logs using by using the [LogQL][logql] query `{zone="us-east-2"}`.
+
+![Grafana Loki logs][ec2 logs]
+
+## Sending systemd logs
+
+Just like we did with Promtail, you'll most likely manage your applications with [systemd][systemd] which usually store applications logs in [journald][journald]. Promtail actually support scraping logs from [journald][journald] so let's configure it.
+
+We will edit our previous config (`vi ec2-promtail.yaml`) and add the following block in the `scrape_configs` section.
+
+```yaml
+  - job_name: journal
+    journal:
+      json: false
+      max_age: 12h
+      path: /var/log/journal
+      labels:
+        job: systemd-journal
+    relabel_configs:
+      - source_labels: ['__journal__systemd_unit']
+        target_label: 'unit'
+```
+
+Note that you can use [relabeling][relabeling] to convert systemd labels to match what you want. Finally make sure that the path of journald logs is correct, it might be different on some systems.
+
+> You can download the final config example in [our repository][final config].
+
+That's it, save the config and you can `reboot` the machine (or simply restart the service `systemctl restart promtail.service`).
+
+Let's head back to Grafana and verify that your Promtail logs are available in Grafana by using the [LogQL][logql] query `{unit="promtail.service"}` in Explore. Finally make sure to checkout [live tailing][live tailing] to see logs appearing as they are ingested in Loki.
+
+[promtail]: ../../promtail/README.md
+[aws cli]: https://aws.amazon.com/cli/
+[create an vpc]: https://docs.aws.amazon.com/vpc/latest/userguide/vpc-subnets-commands-example.html
+[create an ssh key]: https://confluence.atlassian.com/bitbucketserver/creating-ssh-keys-776639788.html
+[GrafanaCloud]: https://grafana.com/signup/
+[terraform]: https://www.terraform.io/
+[cloud formation]: https://aws.amazon.com/fr/cloudformation/
+[ansible]: https://www.ansible.com/
+[chef]: https://www.chef.io/
+[security group]: https://docs.aws.amazon.com/vpc/latest/userguide/VPC_SecurityGroups.html
+[Amazon Linux 2]: https://aws.amazon.com/amazon-linux-2/
+[promtail configuration]: ../../promtail/configuration.md
+[prometheus scrape config]: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config
+[ec2_sd_config]: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#ec2_sd_config
+[role]: https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html
+[discovery page]: ./promtail-ec2-discovery.png "Service discovery"
+[relabel]: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config
+[systemd]: https://www.freedesktop.org/software/systemd/man/systemd.service.html
+[logql]: ../../../logql.md
+[ec2 logs]: ./promtail-ec2-logs.png "Grafana Loki logs"
+[config gist]: https://gist.github.com/cyriltovena/d0881cc717757db951b642be48c01445
+[labels]: https://grafana.com/blog/2020/04/21/how-labels-in-loki-can-make-log-queries-faster-and-easier/
+[troubleshooting loki]: ../../../getting-started/troubleshooting.md#troubleshooting-targets
+[live tailing]: https://grafana.com/docs/grafana/latest/features/datasources/loki/#live-tailing
+[systemd]: https://github.com/grafana/loki/tree/master/production/helm/promtail#run-promtail-with-systemd-journal-support
+[journald]: https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html
+[final config]: https://github.com/grafana/loki/blob/master/docs/clients/aws/ec2/promtail-ec2-final.yaml
+[relabeling]: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config
--- a/docs/clients/aws/ec2/promtail-ec2-discovery.png
+++ b/docs/clients/aws/ec2/promtail-ec2-discovery.png
--- a/docs/clients/aws/ec2/promtail-ec2-final.yaml
+++ b/docs/clients/aws/ec2/promtail-ec2-final.yaml
@ -0,0 +1,42 @@
+server:
+  http_listen_port: 3100
+  grpc_listen_port: 0
+
+clients:
+  - url: https://<user id>:<api secret>@logs-prod-us-central1.grafana.net/loki/api/v1/push
+
+positions:
+  filename: /opt/promtail/positions.yaml
+
+scrape_configs:
+  - job_name: journal
+    journal:
+      json: false
+      max_age: 12h
+      path: /var/log/journal
+      labels:
+        job: systemd-journal
+    relabel_configs:
+      - source_labels: ["__journal__systemd_unit"]
+        target_label: "unit"
+  - job_name: ec2-logs
+    ec2_sd_configs:
+      - region: us-east-2
+        access_key: REDACTED
+        secret_key: REDACTED
+    relabel_configs:
+      - source_labels: [__meta_ec2_tag_Name]
+        target_label: name
+        action: replace
+      - source_labels: [__meta_ec2_instance_id]
+        target_label: instance
+        action: replace
+      - source_labels: [__meta_ec2_availability_zone]
+        target_label: zone
+        action: replace
+      - action: replace
+        replacement: /var/log/**.log
+        target_label: __path__
+      - source_labels: [__meta_ec2_private_dns_name]
+        regex: "(.*)"
+        target_label: __host__
--- a/docs/clients/aws/ec2/promtail-ec2-logs.png
+++ b/docs/clients/aws/ec2/promtail-ec2-logs.png
--- a/docs/clients/aws/ec2/promtail-ec2.yaml
+++ b/docs/clients/aws/ec2/promtail-ec2.yaml
@ -0,0 +1,32 @@
+server:
+  http_listen_port: 3100
+  grpc_listen_port: 0
+
+clients:
+  - url: https://<user id>:<api secret>@logs-prod-us-central1.grafana.net/loki/api/v1/push
+
+positions:
+  filename: /opt/promtail/positions.yaml
+
+scrape_configs:
+  - job_name: ec2-logs
+    ec2_sd_configs:
+      - region: us-east-2
+        access_key: REDACTED
+        secret_key: REDACTED
+    relabel_configs:
+      - source_labels: [__meta_ec2_tag_Name]
+        target_label: name
+        action: replace
+      - source_labels: [__meta_ec2_instance_id]
+        target_label: instance
+        action: replace
+      - source_labels: [__meta_ec2_availability_zone]
+        target_label: zone
+        action: replace
+      - action: replace
+        replacement: /var/log/**.log
+        target_label: __path__
+      - source_labels: [__meta_ec2_private_dns_name]
+        regex: "(.*)"
+        target_label: __host__
--- a/docs/clients/aws/ec2/promtail.service
+++ b/docs/clients/aws/ec2/promtail.service
@ -0,0 +1,13 @@
+[Unit]
+Description=Promtail
+[Service]
+User=root
+WorkingDirectory=/opt/promtail/
+ExecStartPre=/bin/sleep 30
+ExecStart=/opt/promtail/promtail-linux-amd64 --config.file=./ec2-promtail.yaml
+SuccessExitStatus=143
+TimeoutStopSec=10
+Restart=on-failure
+RestartSec=5
+[Install]
+WantedBy=multi-user.target
--- a/docs/clients/promtail/README.md
+++ b/docs/clients/promtail/README.md
@ -47,6 +47,10 @@ There are a few instances where this might be helpful:
 When the [Syslog Target](./configuration.md#syslog_config) is being used, logs
 can be written with the syslog protocol to the configured port.

+## AWS
+
+If you need to run Promtail on Amazon Web Services EC2 instances, you can use our [detailed tutorial](../aws/ec2/ec2.md).
+
 ## Labeling and parsing

 During service discovery, metadata is determined (pod name, filename, etc.) that