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Export Events with Fluentd

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Forwarding Access Logs using FluentD

Forwarding Access Logs using FluentD

Length: 18:36

Fluentd is an open-source data collector for a unified logging layer. In this guide, we will:

  • Set up Teleport's Event Handler plugin.
  • Forward events with Fluentd.

This guide also serves as an explanation for the Teleport Event Handler plugin, using Fluentd as the target service. We'll create a local Docker container as a destination for the Event Handler:

You can follow the instructions below for a local proof-of-concept demo, or use any of the additional installation instructions to configure the Teleport Event Handler to integrate with your infrastructure.

Prerequisites

  • A running Teleport cluster. For details on how to set this up, see one of our Getting Started guides.

  • The tctl admin tool and tsh client tool version >= 13.0.3.

    tctl version

    Teleport v13.0.3 go1.20

    tsh version

    Teleport v13.0.3 go1.20

    See Installation for details.

  • A running Teleport Enterprise cluster. For details on how to set this up, see our Enterprise Getting Started guide.

  • The Enterprise tctl admin tool and tsh client tool version >= 13.0.3, which you can download by visiting your Teleport account.

    tctl version

    Teleport Enterprise v13.0.3 go1.20

    tsh version

    Teleport v13.0.3 go1.20

Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.
  • Fluentd version v1.12.4 or greater.

  • Docker version v20.10.7.

  • Make sure you can connect to Teleport. Log in to your cluster using tsh, then use tctl remotely:

    tsh login --proxy=teleport.example.com [email protected]
    tctl status

    Cluster teleport.example.com

    Version 13.0.3

    CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

    You can run subsequent tctl commands in this guide on your local machine.

    For full privileges, you can also run tctl commands on your Auth Service host.

  • On your workstation, create a folder called event-handler, to hold configuration files and plugin state:

    mkdir -p event-handler
    cd event-handler

Step 1/6. Install the event handler plugin

The Teleport event handler runs alongside the Fluentd forwarder, receives events from Teleport's events API, and forwards them to Fluentd.

curl -L -O https://get.gravitational.com/teleport-event-handler-v13.0.3-linux-amd64-bin.tar.gz
tar -zxvf teleport-event-handler-v13.0.3-linux-amd64-bin.tar.gz

We currently only build the Event Handler plugin for amd64 machines. For ARM architecture, you can build from source.

curl -L -O https://get.gravitational.com/teleport-event-handler-v13.0.3-darwin-amd64-bin.tar.gz
tar -zxvf teleport-event-handler-v13.0.3-darwin-amd64-bin.tar.gz

We currently only build the event handler plugin for amd64 machines. If your macOS machine uses Apple silicon, you will need to install Rosetta before you can run the event handler plugin. You can also build from source.

Ensure that you have Docker installed and running.

docker pull public.ecr.aws/gravitational/teleport-plugin-event-handler:13.0.3

To allow Helm to install charts that are hosted in the Teleport Helm repository, use helm repo add:

helm repo add teleport https://charts.releases.teleport.dev

To update the cache of charts from the remote repository, run helm repo update:

helm repo update

Ensure that you have Docker installed and running.

Run the following commands to build the plugin:

git clone https://github.com/gravitational/teleport-plugins.git --depth 1
cd teleport-plugins/event-handler/build.assets
make build

You can find the compiled binary within your clone of the teleport-plugins repo, with the file path, event-handler/build/teleport-event-handler.

You will need Go >= 1.20 installed.

Run the following commands on your Universal Forwarder host:

git clone https://github.com/gravitational/teleport-plugins.git --depth 1
cd teleport-plugins/event-handler
go build

The resulting executable will have the name event-handler. To follow the rest of this guide, rename this file to teleport-event-handler and move it to /usr/local/bin.

Step 2/6. Configure the plugin

Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.

Run the configure command to generate a sample configuration. Replace teleport.example.com:443 with the DNS name and HTTPS port of Teleport's Proxy Service:

./teleport-event-handler configure . teleport.example.com:443

Run the configure command to generate a sample configuration. Assign TELEPORT_CLUSTER_ADDRESS to the DNS name and port of your Teleport Auth Service or Proxy Service:

TELEPORT_CLUSTER_ADDRESS=mytenant.teleport.sh:443
docker run -v `pwd`:/opt/teleport-plugin -w /opt/teleport-plugin public.ecr.aws/gravitational/teleport-plugin-event-handler:13.0.3 configure . ${TELEPORT_CLUSTER_ADDRESS?}

In order to export audit events, you'll need to have the root certificate and the client credentials available as a secret. Use the following command to create that secret in Kubernetes:

kubectl create secret generic teleport-event-handler-client-tls --from-file=ca.crt=ca.crt,client.crt=client.crt,client.key=client.key

This will pack the content of ca.crt, client.crt, and client.key into the secret so the Helm chart can mount them to their appropriate path.

You'll see the following output:

Teleport event handler 0.0.1 07617b0ad0829db043fe779faf1669defdc8d84e

[1] mTLS Fluentd certificates generated and saved to ca.crt, ca.key, server.crt, server.key, client.crt, client.key
[2] Generated sample teleport-event-handler role and user file teleport-event-handler-role.yaml
[3] Generated sample fluentd configuration file fluent.conf
[4] Generated plugin configuration file teleport-event-handler.toml

Follow-along with our getting started guide:

https://goteleport.com/setup/guides/fluentd

The plugin generates several setup files:

ls -l

-rw------- 1 bob bob 1038 Jul 1 11:14 ca.crt

-rw------- 1 bob bob 1679 Jul 1 11:14 ca.key

-rw------- 1 bob bob 1042 Jul 1 11:14 client.crt

-rw------- 1 bob bob 1679 Jul 1 11:14 client.key

-rw------- 1 bob bob 541 Jul 1 11:14 fluent.conf

-rw------- 1 bob bob 1078 Jul 1 11:14 server.crt

-rw------- 1 bob bob 1766 Jul 1 11:14 server.key

-rw------- 1 bob bob 260 Jul 1 11:14 teleport-event-handler-role.yaml

-rw------- 1 bob bob 343 Jul 1 11:14 teleport-event-handler.toml

File(s)Purpose
ca.crt and ca.keySelf-signed CA certificate and private key for Fluentd
server.crt and server.keyFluentd server certificate and key
client.crt and client.keyFluentd client certificate and key, all signed by the generated CA
teleport-event-handler-role.yamluser and role resource definitions for Teleport's event handler
fluent.confFluentd plugin configuration

If you have an existing Fluentd setup with TLS, issue a client certificate and key from the same certificate authority for the Teleport Event Handler to use.

Step 3/6. Create a user and role for reading audit events

The teleport-event-handler configure command generated a file called teleport-event-handler-role.yaml. This file defines a teleport-event-handler role and a user with read-only access to the event API:

kind: role
metadata:
  name: teleport-event-handler
spec:
  allow:
    rules:
      - resources: ['event', 'session']
        verbs: ['list','read']
version: v5
---
kind: user
metadata:
  name: teleport-event-handler
spec:
  roles: ['teleport-event-handler']
version: v2

Move this file to your workstation (or recreate it by pasting the snippet above) and use tctl on your workstation to create the role and the user:

tctl create -f teleport-event-handler-role.yaml

user "teleport-event-handler" has been created

role 'teleport-event-handler' has been created

Step 4/6. Create teleport-event-handler credentials

Enable impersonation of the Fluentd plugin user

In order for the Fluentd plugin to forward events from your Teleport cluster, it needs a signed identity file from the cluster's certificate authority. The Fluentd user cannot request this itself, and requires another user to impersonate this account in order to request a certificate.

Create a role that enables your user to impersonate the Fluentd user. First, paste the following YAML document into a file called teleport-event-handler-impersonator.yaml:

kind: role
version: v5
metadata:
  name: teleport-event-handler-impersonator
spec:
  # SSH options used for user sessions
  options:
    # max_session_ttl defines the TTL (time to live) of SSH certificates
    # issued to the users with this role.
    max_session_ttl: 10h

  # allow section declares a list of resource/verb combinations that are
  # allowed for the users of this role. by default nothing is allowed.
  allow:
    impersonate:
      users: ["teleport-event-handler"]
      roles: ["teleport-event-handler"]

Next, create the role:

tctl create -f teleport-event-handler-impersonator.yaml

Assign the teleport-event-handler-impersonator role to your Teleport user by running the following commands, depending on whether you authenticate as a local Teleport user or via the github, saml, or oidc authentication connectors:

Retrieve your local user's configuration resource:

tctl get users/$(tsh status -f json | jq -r '.active.username') > out.yaml

Edit out.yaml, adding teleport-event-handler-impersonator to the list of existing roles:

  roles:
   - access
   - auditor
   - editor
+  - teleport-event-handler-impersonator

Apply your changes:

tctl create -f out.yaml

Retrieve your github configuration resource:

tctl get github/github --with-secrets > github.yaml

Edit github.yaml, adding teleport-event-handler-impersonator to the teams_to_roles section. The team you will map to this role will depend on how you have designed your organization's RBAC, but it should be the smallest team possible within your organization. This team must also include your user.

Here is an example:

  teams_to_roles:
    - organization: octocats
      team: admins
      roles:
        - access
+       - teleport-event-handler-impersonator

Apply your changes:

tctl create -f github.yaml
Warning

Note the --with-secrets flag in the tctl get command. This adds the value of spec.signing_key_pair.private_key to github.yaml. This is a sensitive value, so take precautions when creating this file and remove it after updating the resource.

Retrieve your saml configuration resource:

tctl get --with-secrets saml/mysaml > saml.yaml

Edit saml.yaml, adding teleport-event-handler-impersonator to the attributes_to_roles section. The attribute you will map to this role will depend on how you have designed your organization's RBAC, but it should be the smallest group possible within your organization. This group must also include your user.

Here is an example:

  attributes_to_roles:
    - name: "groups"
      value: "my-group"
      roles:
        - access
+       - teleport-event-handler-impersonator

Apply your changes:

tctl create -f saml.yaml
Warning

Note the --with-secrets flag in the tctl get command. This adds the value of spec.signing_key_pair.private_key to saml.yaml. This is a sensitive value, so take precautions when creating this file and remove it after updating the resource.

Retrieve your oidc configuration resource:

tctl get oidc/myoidc --with-secrets > oidc.yaml

Edit oidc.yaml, adding teleport-event-handler-impersonator to the claims_to_roles section. The claim you will map to this role will depend on how you have designed your organization's RBAC, but it should be the smallest group possible within your organization. This group must also include your user.

Here is an example:

  claims_to_roles:
    - name: "groups"
      value: "my-group"
      roles:
        - access
+       - teleport-event-handler-impersonator

Apply your changes:

tctl create -f oidc.yaml
Warning

Note the --with-secrets flag in the tctl get command. This adds the value of spec.signing_key_pair.private_key to oidc.yaml. This is a sensitive value, so take precautions when creating this file and remove it after updating the resource.

Log out of your Teleport cluster and log in again to assume the new role.

Export an identity file for the Fluentd plugin user

The Fluentd Teleport plugin uses the teleport-event-handler role and user to read events. We export an identity file for the user with the tctl auth sign command.

tctl auth sign --user=teleport-event-handler --out=identity

This command creates one PEM-encoded file, identity. The identity file includes both TLS and SSH credentials. The Event Handler plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.
Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.

Step 5/6. Start the Fluentd forwarder

The Fluentd plugin will send events to your Fluentd instance using keys generated on the previous step.

The fluent.conf file generated earlier configures your Fluentd instance to accept events using TLS and print them:

<source>
    @type http
    port 8888

    <transport tls>
        client_cert_auth true

        # We are going to run fluentd in Docker. /keys will be mounted from the host file system.
        ca_path /keys/ca.crt
        cert_path /keys/server.crt
        private_key_path /keys/server.key
        private_key_passphrase ********** # Passphrase generated along with the keys
    </transport>

    <parse>
      @type json
      json_parser oj

      # This time format is used by the plugin. This field is required.
      time_type string
      time_format %Y-%m-%dT%H:%M:%S
    </parse>

    # If the number of events is high, fluentd will start failing the ingestion
    # with the following error message: buffer space has too many data errors.
    # The following configuration prevents data loss in case of a restart and
    # overcomes the limitations of the default fluentd buffer configuration.
    # This configuration is optional.
    # See https://docs.fluentd.org/configuration/buffer-section for more details.
    <buffer>
      @type file
      flush_thread_count 8
      flush_interval 1s
      chunk_limit_size 10M
      queue_limit_length 16
      retry_max_interval 30
      retry_forever true
    </buffer>
</source>

# Events sent to test.log will be dumped to STDOUT.
<match test.log>
  @type stdout
</match>

To try out this Fluentd configuration, start your fluentd instance:

docker run -u $(id -u ${USER}):$(id -g ${USER}) -p 8888:8888 -v $(pwd):/keys -v $(pwd)/fluent.conf:/fluentd/etc/fluent.conf fluent/fluentd:edge

This will consume your current terminal, so open a new one to continue following along.

Step 6/6. Start the event handler plugin

Earlier, we generated a file called teleport-event-handler.toml to configure the Fluentd event handler. This file includes setting similar to the following:

Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.
storage = "./storage"
timeout = "10s"
batch = 20
namespace = "default"

[forward.fluentd]
ca = "/home/bob/event-handler/ca.crt"
cert = "/home/bob/event-handler/client.crt"
key = "/home/bob/event-handler/client.key"
url = "https://localhost:8888/test.log"

[teleport]
addr = "example.teleport.com:443"
identity = "identity"

To start the Event Handler, run the following command:

./teleport-event-handler start --config teleport-event-handler.toml

Use the following template to create teleport-plugin-event-handler-values.yaml:

eventHandler:
  storagePath: "./storage"
  timeout: "10s"
  batch: 20
  namespace: "default"

teleport:
  address: "example.teleport.com:443"
  identitySecretName: teleport-event-handler-identity

fluentd:
  url: "https://fluentd.fluentd.svc.cluster.local/events.log"
  sessionUrl: "https://fluentd.fluentd.svc.cluster.local/session.log"
  certificate:
    secretName: "teleport-event-handler-client-tls"
    caPath: "ca.crt"
    certPath: "client.crt"
    keyPath: "client.key"

persistentVolumeClaim:
  enabled: true

To start the event handler in Kubernetes, run the following command:

helm install teleport-plugin-event-handler teleport/teleport-plugin-event-handler \ --values teleport-plugin-event-handler-values.yaml \ --version 13.0.3
Note

This example will start exporting from May 5th 2021:

./teleport-event-handler start --config teleport-event-handler.toml --start-time "2021-05-05T00:00:00Z"

The start time can be set only once, on the first run of the tool.

If you want to change the time frame later, remove the plugin state directory that you specified in the storage field of the handler's configuration file.

Once the handler starts, you will see notifications about scanned and forwarded events:

INFO[0046] Event sent id=0b5f2a3e-faa5-4d77-ab6e-362bca0994fc ts="2021-06-08 11:00:56.034 +0000 UTC" type=user.login
...

Troubleshooting connection issues

If the Teleport Event Handler is displaying error logs while connecting to your Teleport Cluster, ensure that:

  • The certificate the Teleport Event Handler is using to connect to your Teleport cluster is not past its expiration date. This is the value of the --ttl flag in the tctl auth sign command, which is 12 hours by default.
  • Ensure that in your Teleport Event Handler configuration file (teleport-event-handler.toml), you have provided the correct host and port for the Teleport Proxy Service or Auth Service.

Next Steps

Read more about impersonation here.

While this guide uses the tctl auth sign command to issue credentials for the Teleport Event Handler, production clusters should use Machine ID for safer, more reliable renewals. Read our guide to getting started with Machine ID.

To see all of the options you can set in the values file for the teleport-plugin-event-handler Helm chart, consult our reference guide.