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Installation and Configuration

Tetragon installation and configuration options

1 - Deploy on Kubernetes

Deploy and manage Tetragon on Kubernetes

The recommended way to deploy Tetragon on a Kubernetes cluster is to use the Helm chart with Helm 3. Tetragon uses the helm.cilium.io repository to release the helm chart.

Install

To install the latest release of the Tetragon helm chart, use the following command.

helm repo add cilium https://helm.cilium.io
helm repo update
helm install tetragon cilium/tetragon -n kube-system

To wait until Tetragon deployment is ready, use the following kubectl command:

kubectl rollout status -n kube-system ds/tetragon -w

Configuration

You can then make modifications to the Tetragon configuration using helm upgrade, see the following example.

helm upgrade tetragon cilium/tetragon -n kube-system --set tetragon.grpc.address=localhost:1337

You can also edit the tetragon-config ConfigMap directly and restart the Tetragon daemonset with:

kubectl edit cm tetragon-config -n kube-system
kubectl rollout restart ds/tetragon -n kube-system

Upgrade

Upgrade Tetragon using a new specific version of the helm chart.

helm upgrade tetragon cilium/tetragon -n kube-system --version 0.9.0

Uninstall

Uninstall Tetragon using the following command.

helm uninstall tetragon -n kube-system

2 - Deploy as a container

Install and manage Tetragon as a container without a Kubernetes cluster

Install

Stable versions

To run a stable version, please check Tetragon quay repository and select which version you want. For example if you want to run the latest version which is v1.1.2 currently.

docker run --name tetragon --rm -d                   \
    --pid=host --cgroupns=host --privileged          \
    -v /sys/kernel/btf/vmlinux:/var/lib/tetragon/btf \
    quay.io/cilium/tetragon:v1.1.2

Unstable-development versions

To run unstable development versions of Tetragon, use the latest tag from Tetragon-CI quay repository. This will run the image that was built from the latest commit available on the Tetragon main branch.

docker run --name tetragon --rm -d                  \
   --pid=host --cgroupns=host --privileged          \
   -v /sys/kernel/btf/vmlinux:/var/lib/tetragon/btf \
   quay.io/cilium/tetragon-ci:latest

Configuration

There are multiple ways to set configuration options:

  1. Append Tetragon controlling settings at the end of the command

    As an example set the file where to export JSON events with --export-filename argument:

    docker run --name tetragon --rm -d \
        --pid=host --cgroupns=host --privileged \
        -v /sys/kernel:/sys/kernel \
        quay.io/cilium/tetragon:v1.1.2 \
        /usr/bin/tetragon --export-filename /var/log/tetragon/tetragon.log
    

    For a complete list of CLI arguments, please check Tetragon daemon configuration.

  2. Environment variables

    docker run --name tetragon --rm -d \
        --pid=host --cgroupns=host --privileged \
        --env "TETRAGON_EXPORT_FILENAME=/var/log/tetragon/tetragon.log" \
        -v /sys/kernel:/sys/kernel \
        quay.io/cilium/tetragon:v1.1.2
    

    Every controlling setting can be set using environment variables. Prefix it with the key word TETRAGON_ then upper case the controlling setting. As an example to set where to export JSON events: --export-filename will be TETRAGON_EXPORT_FILENAME.

    For a complete list of all controlling settings, please check tetragon daemon configuration.

  3. Configuration files mounted as volumes

    On the host machine set the configuration drop-ins inside /etc/tetragon/tetragon.conf.d/ directory according to the configuration examples, then mount it as volume:

    docker run --name tetragon --rm -d \
        --pid=host --cgroupns=host --privileged \
        -v /sys/kernel:/sys/kernel \
        -v /etc/tetragon/tetragon.conf.d/:/etc/tetragon/tetragon.conf.d/ \
        quay.io/cilium/tetragon:v1.1.2
    

    This will map the /etc/tetragon/tetragon.conf.d/ drop-in directory from the host into the container.

See Tetragon daemon configuration reference for further details.

3 - Deploy with a package

Install and manage Tetragon via released packages.

Install

Tetragon will be managed as a systemd service. Tarballs are built and distributed along the assets in the releases.

  1. First download the latest binary tarball, using curl for example to download the amd64 release:

    curl -LO https://github.com/cilium/tetragon/releases/download/v1.1.2/tetragon-v1.1.2-amd64.tar.gz
    
  2. Extract the downloaded archive, and start the install script to install Tetragon. Feel free to inspect the script before starting it.

    tar -xvf tetragon-v1.1.2-amd64.tar.gz
    cd tetragon-v1.1.2-amd64/
    sudo ./install.sh
    

    If Tetragon was successfully installed, the final output should be similar to:

    Tetragon installed successfully!
    
  3. Finally, you can check the Tetragon systemd service.

    sudo systemctl status tetragon
    

    The output should be similar to:

    ● tetragon.service - Tetragon eBPF-based Security Observability and Runtime Enforcement
     Loaded: loaded (/lib/systemd/system/tetragon.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2023-01-23 20:08:16 CET; 5s ago
       Docs: https://github.com/cilium/tetragon/
    Main PID: 138819 (tetragon)
      Tasks: 17 (limit: 18985)
     Memory: 151.7M
        CPU: 913ms
     CGroup: /system.slice/tetragon.service
             └─138819 /usr/local/bin/tetragon
    

Configuration

The default Tetragon configuration shipped with the Tetragon package will be installed in /usr/local/lib/tetragon/tetragon.conf.d/. Local administrators can change the configuration by adding drop-ins inside /etc/tetragon/tetragon.conf.d/ to override the default settings or use the command line flags. To restore default settings, remove any added configuration inside /etc/tetragon/tetragon.conf.d/.

See Tetragon daemon configuration for further details.

Upgrade

To upgrade Tetragon:

  1. Download the new tarball.

    curl -LO https://github.com/cilium/tetragon/releases/download/v1.1.2/tetragon-v1.1.2-amd64.tar.gz
    
  2. Stop the Tetragon service.

    sudo systemctl stop tetragon
    
  3. Remove the old Tetragon version.

    sudo rm -fr /usr/lib/systemd/system/tetragon.service
    sudo rm -fr /usr/local/bin/tetragon
    sudo rm -fr /usr/local/lib/tetragon/
    
  4. Install the upgraded Tetragon version.

    tar -xvf tetragon-v1.1.2-amd64.tar.gz
    cd tetragon-v1.1.2-amd64/
    sudo ./install.sh
    

Uninstall

To completely remove Tetragon run the uninstall.sh script that is provided inside the tarball.

sudo ./uninstall.sh

Or remove it manually.

sudo systemctl stop tetragon
sudo systemctl disable tetragon
sudo rm -fr /usr/lib/systemd/system/tetragon.service
sudo systemctl daemon-reload
sudo rm -fr /usr/local/bin/tetragon
sudo rm -fr /usr/local/bin/tetra
sudo rm -fr /usr/local/lib/tetragon/

To just purge custom settings:

sudo rm -fr /etc/tetragon/

Operating

gRPC API access

To access the gRPC API with tetra client, set --server-address to point to the corresponding address:

sudo tetra --server-address unix:///var/run/tetragon/tetragon.sock getevents

See restrict gRPC API access for further details.

Tetragon Events

By default JSON events are logged to /var/log/tetragon/tetragon.log unless this location is changed. Logs are always rotated into the same directory.

To read real-time JSON events, tailing the logs file is enough.

sudo tail -f /var/log/tetragon/tetragon.log

Tetragon also ships a gRPC client that can be used to receive events.

  1. To print events in json format using tetra gRPC client:

    sudo tetra --server-address "unix:///var/run/tetragon/tetragon.sock" getevents
    
  2. To print events in human compact format:

    sudo tetra --server-address "unix:///var/run/tetragon/tetragon.sock" getevents -o compact
    

What’s next

See Explore security observability events to learn more about how to see the Tetragon events.

4 - Configure Runtime Hooks

Configure Runtime Hooks

See Tetragon Rutime Hooks, for an introduction to the topic.

We use minikube as the example platform because it supports both cri-o and containerd. Also, at the time of this writing, no images that support this have been released, so we build images locally within a checked out repo.

make image image-operator image-rthooks

CRI-O

Setup Minikube

minikube start --driver=kvm2 --container-runtime=cri-o
minikube image load cilium/tetragon:latest
minikube image load cilium/tetragon-operator:latest
minikube image load cilium/tetragon-rthooks:latest
minikube image ls | grep tetragon

The output should be similar to:

localhost/cilium/tetragon:latest
localhost/cilium/tetragon-rthooks:latest
localhost/cilium/tetragon-operator:latest

Install Tetragon

helm install \
   --namespace kube-system \
   --set tetragon.image.override=localhost/cilium/tetragon:latest \
   --set tetragonOperator.image.override=localhost/cilium/tetragon-operator:latest \
   --set rthooks.enabled=true \
   --set rthooks.interface=oci-hooks \
   --set rthooks.image.override=localhost/cilium/tetragon-rthooks:latest \
   tetragon ./install/kubernetes/tetragon
kubecl -n kube-system get pods | grep tetragon

With output similar to:

tetragon-hpjwq                       2/2     Running   0          2m42s
tetragon-operator-664ddc8957-9lmd2   1/1     Running   0          2m42s
tetragon-rthooks-m24xr               1/1     Running   0          2m42s

Test

Start a pod:

kubectl run test --image=debian  --rm -it -- /bin/bash

Check logs:

minikube ssh 'tail -1 /opt/tetragon/tetragon-oci-hook.log'

Output:

{"time":"2024-07-01T10:57:21.435689144Z","level":"INFO","msg":"hook request to agent succeeded","hook":"create-container","start-time":"2024-07-01T10:57:21.433755984Z","req-cgroups":"/kubepods/besteffort/podd4e74de2-0db8-4143-ae55-695b2489c727/crio-828977b42e3149b502b31708778d0c057efbce038af80d0882ed3e0cb0ff8796","req-rootdir":"/run/containers/storage/overlay-containers/828977b42e3149b502b31708778d0c057efbce038af80d0882ed3e0cb0ff8796/userdata","req-containerName":"test"}

Containerd

Setup Minikube

minikube start --driver=kvm2 --container-runtime=containerd
minikube image load cilium/tetragon:latest
minikube image load cilium/tetragon-operator:latest
minikube image load cilium/tetragon-rthooks:latest
minikube image ls | grep tetragon

Output should be similar to:

docker.io/cilium/tetragon:latest
docker.io/cilium/tetragon-rthooks:latest
docker.io/cilium/tetragon-operator:latest

Tetragon Runtime Hooks use NRI. NRI is enabled by default starting from containerd version 2.0. For version 1.7, however, it needs to be enabled in the configuration.

minikube ssh cat /etc/containerd/config.toml > /tmp/old-config.toml
./contrib/tetragon-rthooks/tetragon-oci-hook-setup patch-containerd-conf enable-nri --config-file=/tmp/old-config.toml --output=/tmp/new-config.toml
diff -u /tmp/old-config.toml /tmp/new-config.toml

Output should be something like:

--- /tmp/old-config.toml        2024-07-02 11:51:23.893382357 +0200
+++ /tmp/new-config.toml        2024-07-02 11:51:52.841533035 +0200
@@ -67,3 +67,11 @@
     mutation_threshold = 100
     schedule_delay = "0s"
     startup_delay = "100ms"
+  [plugins."io.containerd.nri.v1.nri"]
+    disable = false
+    disable_connections = false
+    plugin_config_path = "/etc/nri/conf.d"
+    plugin_path = "/opt/nri/plugins"
+    plugin_registration_timeout = "5s"
+    plugin_request_timeout = "2s"
+    socket_path = "/var/run/nri/nri.sock"

Install the new configuration file and restart containerd

minikube cp /tmp/new-config.toml /etc/containerd/config.toml
ssh sudo systemctl restart containerd

Install Tetragon

helm install \
   --namespace kube-system \
   --set tetragon.image.override=docker.io/cilium/tetragon:latest \
   --set tetragonOperator.image.override=docker.io/cilium/tetragon-operator:latest \
   --set rthooks.enabled=true \
   --set rthooks.interface=nri-hook \
   --set rthooks.image.override=docker.io/cilium/tetragon-rthooks:latest \
   tetragon ./install/kubernetes/tetragon
kubectl -n kube-system get pods | grep tetragon

Output should be similar to:

tetragon-operator-754b85cfd4-2mdd7   1/1     Running   0              24m
tetragon-pjrsf                       2/2     Running   0              24m
tetragon-rthooks-6g8cq               1/1     Running   0              24m

Test

Start a pod:

kubectl run test --image=debian  --rm -it -- /bin/bash

Examine the log file:

minikube ssh 'tail -1 /opt/tetragon/tetragon-oci-hook.log'

Output:

{"time":"2024-07-02T12:02:02.823291054Z","level":"INFO","msg":"hook request to agent succeeded","hook":"createRuntime","start-time":"2024-07-02T12:02:02.816185835Z","req-cgroups":"/kubepods/besteffort/pod9305570c-ac68-4f95-96d8-afbb138bd0b0/42469ae2c52d0ee340b550b8a07a142c9b8cc709aa8ca75b777bb00812149621","req-rootdir":"/run/containerd/io.containerd.runtime.v2.task/k8s.io/42469ae2c52d0ee340b550b8a07a142c9b8cc709aa8ca75b777bb00812149621","req-containerName":"test"}

5 - Install tetra CLI

To interact with Tetragon, install the Tetragon client CLI tetra

This guide presents various methods to install tetra in your environment.

Install the latest release

Autodetect your environment

This shell script autodetects the OS and the architecture, downloads the archive of the binary and its SHA 256 digest, compares that the actual digest with the supposed one, installs the binary, and removes the download artifacts.

GOOS=$(go env GOOS)
GOARCH=$(go env GOARCH)
curl -L --remote-name-all https://github.com/cilium/tetragon/releases/latest/download/tetra-${GOOS}-${GOARCH}.tar.gz{,.sha256sum}
sha256sum --check tetra-${GOOS}-${GOARCH}.tar.gz.sha256sum
sudo tar -C /usr/local/bin -xzvf tetra-${GOOS}-${GOARCH}.tar.gz
rm tetra-${GOOS}-${GOARCH}.tar.gz{,.sha256sum}

Quick install for each environment

This installation method retrieves the adapted archived for your environment, extract it and install it in the /usr/local/bin directory.

curl -L https://github.com/cilium/tetragon/releases/latest/download/tetra-linux-amd64.tar.gz | tar -xz
sudo mv tetra /usr/local/bin
curl -L https://github.com/cilium/tetragon/releases/latest/download/tetra-linux-arm64.tar.gz | tar -xz
sudo mv tetra /usr/local/bin
curl -L https://github.com/cilium/tetragon/releases/latest/download/tetra-darwin-amd64.tar.gz | tar -xz
sudo mv tetra /usr/local/bin
curl -L https://github.com/cilium/tetragon/releases/latest/download/tetra-darwin-arm64.tar.gz | tar -xz
sudo mv tetra /usr/local/bin
curl -LO https://github.com/cilium/tetragon/releases/latest/download/tetra-windows-amd64.tar.gz
tar -xzf tetra-windows-amd64.tar.gz
# move the binary in a directory in your PATH
curl -LO https://github.com/cilium/tetragon/releases/latest/download/tetra-windows-arm64.tar.gz
tar -xzf tetra-windows-arm64.tar.gz
# move the binary in a directory in your PATH

Install using homebrew

Homebrew is a package manager for macOS and Linux. A formulae is available to fetch precompiled binaries. You can also use it to build from sources (using the --build-from-source flag) with a Go dependency.

brew install tetra

Install a specific release

You can retrieve the release of tetra along the release of Tetragon on GitHub at the following URL: https://github.com/cilium/tetragon/releases.

To download a specific release you can use the following script, replacing the OS, ARCH and TAG values with your desired options.

OS=linux
ARCH=amd64
TAG=v0.9.0
curl -LO https://github.com/cilium/tetragon/releases/download/${TAG}/tetra-${OS}-${ARCH}.tar.gz | tar -xz

6 - Verify installation

Verify Tetragon image and software bill of materials signatures

Verify Tetragon image signature

Learn how to verify Tetragon container images signatures.

Prerequisites

You will need to install cosign.

Verify Signed Container Images

Since version 0.8.4, all Tetragon container images are signed using cosign.

Let’s verify a Tetragon image’s signature using the cosign verify command:

cosign verify --certificate-github-workflow-repository cilium/tetragon --certificate-oidc-issuer https://token.actions.githubusercontent.com <Image URL> | jq

Verify the SBOM signature

Download and verify the signature of the software bill of materials

A Software Bill of Materials (SBOM) is a complete, formally structured list of components that are required to build a given piece of software. SBOM provides insight into the software supply chain and any potential concerns related to license compliance and security that might exist.

Starting with version 0.8.4, all Tetragon images include an SBOM. The SBOM is generated in SPDX format using the bom tool. If you are new to the concept of SBOM, see what an SBOM can do for you.

Download SBOM

The SBOM can be downloaded from the supplied Tetragon image using the cosign download sbom command.

cosign download sbom --output-file sbom.spdx <Image URL>

Verify SBOM Image Signature

To ensure the SBOM is tamper-proof, its signature can be verified using the cosign verify command.

COSIGN_EXPERIMENTAL=1 cosign verify --certificate-github-workflow-repository cilium/tetragon --certificate-oidc-issuer https://token.actions.githubusercontent.com --attachment sbom <Image URL> | jq

It can be validated that the SBOM image was signed using Github Actions in the Cilium repository from the Issuer and Subject fields of the output.

7 - Configure Tetragon

Depending on your deployment mode, Tetragon configuration can be changed by:

kubectl edit cm -n kube-system tetragon-config
# Change your configuration setting, save and exit
# Restart Tetragon daemonset
kubectl rollout restart -n kube-system ds/tetragon
# Change configuration inside /etc/tetragon/ then restart container.
# Example:
#   1. As a privileged user, write to the file /etc/tetragon/tetragon.conf.d/export-file
#      the path where to export events, example "/var/log/tetragon/tetragon.log"
#   2. Bind mount host /etc/tetragon into container /etc/tetragon
# Tetragon events will be exported to /var/log/tetragon/tetragon.log
echo "/var/log/tetragon/tetragon.log" > /etc/tetragon/tetragon.conf.d/export-file
docker run --name tetragon --rm -d \
  --pid=host --cgroupns=host --privileged \
  -v /etc/tetragon:/etc/tetragon \
  -v /sys/kernel:/sys/kernel \
  -v /var/log/tetragon:/var/log/tetragon \
  quay.io/cilium/tetragon:v1.1.2 \
  /usr/bin/tetragon
# Change configuration inside /etc/tetragon/ then restart systemd service.
# Example:
#   1. As a privileged user, write to the file /etc/tetragon/tetragon.conf.d/export-file
#      the path where to export events, example "/var/log/tetragon/tetragon.log"
#   2. Bind mount host /etc/tetragon into container /etc/tetragon
# Tetragon events will be exported to /var/log/tetragon/tetragon.log
echo "/var/log/tetragon/tetragon.log" > /etc/tetragon/tetragon.conf.d/export-file
systemctl restart tetragon

To read more about Tetragon configuration, please check our reference pages:

Enable Process Credentials

On Linux each process has various associated user, group IDs and capabilities known as process credentials. To enable visility into process_credentials, run Tetragon with enable-process-creds setting set.

kubectl edit cm -n kube-system tetragon-config
# Change "enable-process-cred" from "false" to "true", then save and exit
# Restart Tetragon daemonset
kubectl rollout restart -n kube-system ds/tetragon
echo "true" > /etc/tetragon/tetragon.conf.d/enable-process-cred
docker run --name tetragon --rm -d \
  --pid=host --cgroupns=host --privileged \
  -v /etc/tetragon:/etc/tetragon \
  -v /sys/kernel:/sys/kernel \
  -v /var/log/tetragon:/var/log/tetragon \
  quay.io/cilium/tetragon:v1.1.2 \
  /usr/bin/tetragon
# Write to the drop-in file /etc/tetragon/tetragon.conf.d/enable-process-cred  true
# Run the following as a privileged user then restart tetragon service
echo "true" > /etc/tetragon/tetragon.conf.d/enable-process-cred
systemctl restart tetragon

8 - Metrics

Learn how to configure and access Prometheus metrics.

Tetragon exposes a number of Prometheus metrics that can be used for two main purposes:

  1. Monitoring the health of Tetragon itself
  2. Monitoring the activity of processes observed by Tetragon

For the full list, refer to metrics reference.

Enable/Disable Metrics

Kubernetes

In a Kubernetes installation, metrics are enabled by default and exposed via tetragon service at endpoint /metrics on port 2112.

You can change the port via Helm values:

tetragon:
  prometheus:
    port: 2222 # default is 2112

Or entirely disable the metrics server:

tetragon:
  prometheus:
    enabled: false # default is true

Non-Kubernetes

In a non-Kubernetes installation, metrics are disabled by default. You can enable them by setting the metrics server address, for example :2112, via the --metrics-server flag.

If using systemd, set the metrics-address entry in a file under the /etc/tetragon/tetragon.conf.d/ directory.

Verify that metrics are exposed

To verify that the metrics server has started, check the logs of the Tetragon Agent. In Kubernetes, run:

kubectl -n kube-system logs ds/tetragon

The logs should contain a line similar to the following:

time="2023-09-22T23:16:24+05:30" level=info msg="Starting metrics server" addr="localhost:2112"

To see what metrics are exposed, you can access the metrics endpoint directly. In Kubernetes, forward the metrics port:

kubectl -n kube-system port-forward svc/tetragon 2112:2112

Access localhost:2112/metrics endpoint either in a browser or for example using curl. You should see a list of metrics similar to the following:

# HELP promhttp_metric_handler_errors_total Total number of internal errors encountered by the promhttp metric handler.
# TYPE promhttp_metric_handler_errors_total counter
promhttp_metric_handler_errors_total{cause="encoding"} 0
promhttp_metric_handler_errors_total{cause="gathering"} 0
# HELP tetragon_errors_total The total number of Tetragon errors. For internal use only.
# TYPE tetragon_errors_total counter
[...]

Configure labels on events metrics

Depending on the workloads running in the environment, Events Metrics may have very high cardinality. This is particularly likely in Kubernetes environments, where each pod creates a separate timeseries. To avoid overwhelming Prometheus, Tetragon provides an option to choose which labels are populated in these metrics.

You can configure the labels via Helm values or the --metrics-label-filter flag. Set the value to a comma-separated list of enabled labels:

tetragon:
  prometheus:
    metricsLabelFilter: "namespace,workload,binary" # "pod" label is disabled

Scrape metrics

Typically, metrics are scraped by Prometheus or another compatible agent (for example OpenTelemetry Collector), stored in Prometheus or another compatible database, then queried and visualized for example using Grafana.

In Kubernetes, you can install Prometheus and Grafana using the kube-prometheus-stack Helm chart:

helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm install kube-prometheus-stack prometheus-community/kube-prometheus-stack \
  --namespace monitoring  --create-namespace \
  --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false

The kube-prometheus-stack Helm chart includes Prometheus Operator, which allows you to configure Prometheus via Kubernetes custom resources. Tetragon comes with a default ServiceMonitor resource containing the scrape confguration. You can enable it via Helm values:

tetragon:
  prometheus:
    serviceMonitor:
      enabled: true

9 - FAQ

List of frequently asked questions

What is the minimum Linux kernel version to run Tetragon?

Tetragon needs Linux kernel version 4.19 or greater.

We currently run tests on stable long-term support kernels 4.19, 5.4, 5.10, 5.15 and bpf-next, see this test workflow for up to date information. Not all Tetragon features work with older kernel versions. BPF evolves rapidly and we recommend you use the most recent stable kernel possible to get the most out of Tetragon’s features.

Note that Tetragon needs BTF support which might take some work on older kernels.

What are the Linux kernel configuration options needed to run Tetragon?

This is the list of needed configuration options, note that this might evolve quickly with new Tetragon features:

# CORE BPF
CONFIG_BPF
CONFIG_BPF_JIT
CONFIG_BPF_JIT_DEFAULT_ON
CONFIG_BPF_EVENTS
CONFIG_BPF_SYSCALL
CONFIG_HAVE_BPF_JIT
CONFIG_HAVE_EBPF_JIT
CONFIG_FTRACE_SYSCALLS

# BTF
CONFIG_DEBUG_INFO_BTF
CONFIG_DEBUG_INFO_BTF_MODULES

# Enforcement
CONFIG_BPF_KPROBE_OVERRIDE

# CGROUP and Process tracking
CONFIG_CGROUPS=y        Control Group support
CONFIG_MEMCG=y          Memory Control group
CONFIG_BLK_CGROUP=y     Generic block IO controller
CONFIG_CGROUP_SCHED=y
CONFIG_CGROUP_PIDS=y    Process Control group
CONFIG_CGROUP_FREEZER=y Freeze and unfreeze tasks controller
CONFIG_CPUSETS=y        Manage CPUSETs
CONFIG_PROC_PID_CPUSET=y
CONFIG_CGROUP_DEVICE=Y  Devices Control group
CONFIG_CGROUP_CPUACCT=y CPU accouting controller
CONFIG_CGROUP_PERF=y
CONFIG_CGROUP_BPF=y     Attach eBPF programs to a cgroup
CGROUP_FAVOR_DYNMODS=y  (optional)  >= 6.0
  Reduces the latencies of dynamic cgroup modifications at the
  cost of making hot path operations such as forks and exits
  more expensive.
  Platforms with frequent cgroup migrations could enable this
  option as a potential alleviation for pod and containers
  association issues.

At runtime, to probe if your kernel has sufficient features turned on, you can run tetra with root privileges with the probe command:

sudo tetra probe

You can also run this command directly from the tetragon container image on a Kubernetes cluster node. For example:

kubectl run bpf-probe --image=quay.io/cilium/tetragon-ci:latest --privileged --restart=Never -it --rm --command -- tetra probe

The output should be similar to this (with boolean values depending on your actual configuration):

override_return: true
buildid: true
kprobe_multi: false
fmodret: true
fmodret_syscall: true
signal: true
large: true

Tetragon failed to start complaining about a missing BTF file

You might have encountered the following issues:

level=info msg="BTF discovery: default kernel btf file does not exist" btf-file=/sys/kernel/btf/vmlinux
level=info msg="BTF discovery: candidate btf file does not exist" btf-file=/var/lib/tetragon/metadata/vmlinux-5.15.49-linuxkit
level=info msg="BTF discovery: candidate btf file does not exist" btf-file=/var/lib/tetragon/btf
[...]
level=fatal msg="Failed to start tetragon" error="tetragon, aborting kernel autodiscovery failed: Kernel version \"5.15.49-linuxkit\" BTF search failed kernel is not included in supported list. Please check Tetragon requirements documentation, then use --btf option to specify BTF path and/or '--kernel' to specify kernel version"

Tetragon needs BTF (BPF Type Format) support to load its BPF programs using CO-RE (Compile Once - Run Everywhere). In brief, CO-RE is useful to load BPF programs that have been compiled on a different kernel version than the target kernel. Indeed, kernel structures change between versions and BPF programs need to access fields in them. So CO-RE uses the BTF file of the kernel in which you are loading the BPF program to know the differences between the struct and patch the fields offset in the accessed structures. CO-RE allows portability of the BPF programs but requires a kernel with BTF enabled.

Most of the common Linux distributions now ship with BTF enabled and do not require any extra work, this is kernel option CONFIG_DEBUG_INFO_BTF=y. To check if BTF is enabled on your Linux system and see the BTF data file of your kernel, the standard location is /sys/kernel/btf/vmlinux. By default, Tetragon will look for this file (this is the first line in the log output above).

If your kernel does not support BTF you can:

  • Retrieve the BTF file for your kernel version from an external source.
  • Build the BTF file from your kernel debug symbols. You will need pahole to add BTF metadata to the debugging symbols and LLVM minimize the medata size.
  • Rebuild your kernel with CONFIG_DEBUG_INFO_BTF to y.

Tetragon will also look into /var/lib/tetragon/btf for the vmlinux file (this is the third line in the log output above). Or you can use the --btf flag to directly indicate Tetragon where to locate the file.

If you encounter this issue while using Docker Desktop on macOS, please refer to can I run Tetragon on Mac computers.

Can I install and use Tetragon in standalone mode (outside of k8s)?

Yes! Refer to the Container or Package installation guides.

Otherwise you can build Tetragon from source by running make to generate standalone binaries. Make sure to take a look at the Development Setup guide for the build requirements. Then use sudo ./tetragon --bpf-lib bpf/objs to run Tetragon.

Can I run Tetragon on Mac computers?

Yes! You can run Tetragon locally by running a Linux virtual machine on your Mac.

On macOS running on amd64 (also known as Intel Mac) and arm64 (also know as Apple Silicon Mac), open source and commercial solutions exists to run virtual machines, here is a list of popular open source projects that you can use:

You can use these solutions to run a recent Linux distribution that ships with BTF debug information support.

Please note that you need to use a recent Docker Desktop version on macOS (for example 24.0.6 with Kernel 6.4.16-linuxkit), because the Linux virtual machine provided by older Docker Desktop versions lacked support for the BTF debug information. The BTF debug information file is needed for CO-RE in order to load sensors of Tetragon. Run the following commands to see if Tetragon can be used on your Docker Desktop version:

# The Kernel needs to be compiled with CONFIG_DEBUG_INFO_BTF and
# CONFIG_DEBUG_INFO_BTF_MODULES support:
$ docker run -it --rm --privileged --pid=host ubuntu \
    nsenter -t 1 -m -u -n -i sh -c \
    'cat /proc/config.gz | gunzip | grep CONFIG_DEBUG_INFO_BTF'
CONFIG_DEBUG_INFO_BTF=y
CONFIG_DEBUG_INFO_BTF_MODULES=y

# "/sys/kernel/btf/vmlinux" should be present:
$ docker run -it --rm --privileged --pid=host ubuntu \
    nsenter -t 1 -m -u -n -i sh -c 'ls -la /sys/kernel/btf/vmlinux'
-r--r--r--    1 root     root       4988627 Nov 21 20:33 /sys/kernel/btf/vmlinux