Running

Operating and Managing Falco

Falco packages

If you installed the Falco packages using the dialog all your services should be already up and running, while if you chose the Manual configuration or if you used the FALCO_FRONTEND=noninteractive env variable you have to configure services by your hand. Here we show a simple example with the eBPF probe.

Let's imagine we want to start the falco-bpf.service.

  1. Type systemctl list-units | grep falco to check that no unit is running.

  2. Now you have to decide whether you want the Falcoctl service running together with the Falco one. If yes you don't have to do anything, else you will need to mask the Falcoctl service with systemctl mask falcoctl-artifact-follow.service. As pointed out in this section the Falcoctl service is strictly related to the Falco one so if you don't mask it, it will be started together with the Falco service.

  3. Type falcoctl driver config --type ebpf to configure Falco to use eBPF driver, then falcoctl driver install to download/compile the eBPF probe.

  4. Now running systemctl start falco-bpf.service and typing systemctl list-units | grep falco you should see something like that (supposing you didn't mask the Falcoctl service):

    falco-bpf.service                                 loaded active running   Falco: Container Native Runtime Security with ebpf
    falcoctl-artifact-follow.service                  loaded active running   Falcoctl Artifact Follow: automatic artifacts update service
    
  5. If you want to stop both services in one shot

    systemctl stop falco-bpf.service
    

Custom run

You may have noticed a Falco unit called falco-custom.service. You should use it when you want to run Falco with a custom configuration like a plugin or Gvisor. Please note that in this case you have to modify this template according to how you want to run Falco, the unit should not be used as is!

Falco binary

Here you can find some examples of how to run Falco after having installed it using the binary package

# Default driver as set in the Falco config file
falco
# Force eBPF probe
falco -o engine.kind=ebpf
# Force modern eBPF probe
falco -o engine.kind=modern_ebpf
# For more info see all available options
falco --help

If you are using the eBPF probe, in order to ensure that performance is not degraded, make sure that

  • Your kernel has CONFIG_BPF_JIT enabled
  • net.core.bpf_jit_enable is set to 1 (enable the BPF JIT Compiler)
  • This can be verified via sysctl -n net.core.bpf_jit_enable

Docker

To learn how to run Falco from a container in a Kubernetes setting, checkout the Deployment guide next.

Even using container images, Falco needs kernel headers installed on the host as prerequisite to correctly build the driver (the kernel module or the eBPF probe) on the fly. This step is not needed when a prebuilt driver is already available.

You can find instructions on how to install the kernel headers for your system under the Install section.

Falco ships a set of official docker images. The images can be used in two ways as follows:

Least privileged (recommended)

This is how the Falco userspace process can be ran in a container.

Once the kernel module has been installed directly on the host system, it can be used from within a container.

  1. Install the kernel module:

    • You can use an official installation method directly on the host
    • Alternatively, you can temporarily use a privileged container to install the driver on the host:
    docker pull falcosecurity/falco-driver-loader:latest
    docker run --rm -i -t \
        --privileged \
        -v /root/.falco:/root/.falco \
        -v /proc:/host/proc:ro \
        -v /boot:/host/boot:ro \
        -v /lib/modules:/host/lib/modules \
        -v /usr:/host/usr:ro \
        -v /etc:/host/etc:ro \
        falcosecurity/falco-driver-loader:latest
    

The falcosecurity/falco-driver-loader image just wraps the falcoctl driver tool. You can find more about its usage here

  1. Run Falco in a container using Docker with the principle of least privilege:

    docker pull falcosecurity/falco-no-driver:latest
    docker run --rm -i -t \
        -e HOST_ROOT=/ \
        --cap-add SYS_PTRACE --pid=host $(ls /dev/falco* | xargs -I {} echo --device {}) \
        -v /var/run/docker.sock:/var/run/docker.sock \
        -v /etc:/host/etc:ro \
        falcosecurity/falco-no-driver:latest
    

If you are running Falco on a system with the AppArmor LSM enabled (e.g Ubuntu), you will also need to pass --security-opt apparmor:unconfined to the docker run command above.

You can verify if you have AppArmor enabled using the command below:

docker info | grep -i apparmor

Note that ls /dev/falco* | xargs -I {} echo --device {} outputs a --device /dev/falcoX option per CPU (ie. just the devices created by the Falco's kernel module). Also, -e HOST_ROOT=/ is necessary since with --device there is no way to remap devices to /host/dev/.

To run Falco in least privileged mode with the eBPF driver, we list all the required capabilities:

  • on kernels <5.8, Falco requires CAP_SYS_ADMIN, CAP_SYS_RESOURCE and CAP_SYS_PTRACE
  • on kernels >=5.8, CAP_BPF and CAP_PERFMON were separated out of CAP_SYS_ADMIN, so the required capabilities are CAP_BPF, CAP_PERFMON, CAP_SYS_RESOURCE, CAP_SYS_PTRACE. Unfortunately, Docker does not yet support adding the two newly introduced capabilities with the --cap-add option. For this reason, we continue using CAP_SYS_ADMIN, given that it still allows performing the same operations granted by CAP_BPF and CAP_PERFMON. In the near future, Docker will support adding these two capabilities and we will be able to replace CAP_SYS_ADMIN.
  1. Install the eBPF probe

    docker pull falcosecurity/falco-driver-loader:latest
    docker run --rm -i -t \
        --privileged \
        -v /root/.falco:/root/.falco \
        -v /proc:/host/proc:ro \
        -v /boot:/host/boot:ro \
        -v /lib/modules:/host/lib/modules:ro \
        -v /usr:/host/usr:ro \
        -v /etc:/host/etc:ro \
        falcosecurity/falco-driver-loader:latest ebpf
    
  2. Then, run Falco

    docker pull falcosecurity/falco-no-driver:latest
    docker run --rm -i -t \
        --cap-drop all \
        --cap-add sys_admin \
        --cap-add sys_resource \
        --cap-add sys_ptrace \
        -v /var/run/docker.sock:/host/var/run/docker.sock \
        -v /root/.falco:/root/.falco \
        -v /etc:/host/etc \
        -v /proc:/host/proc:ro \
        falcosecurity/falco-no-driver:latest -o engine.kind=ebpf
    
    # Please remember to add '-v /sys/kernel/debug:/sys/kernel/debug:ro \' to the above docker command
    # if you are running a kernel version < 4.14
    

Again, you will need to add --security-opt apparmor:unconfined to the last command if your system has the AppArmor LSM enabled.

Fully privileged

To run Falco in a container using Docker with full privileges use the following commands.

If you want to use Falco with the Kernel module driver:

docker pull falcosecurity/falco:latest
docker run --rm -i -t \
    --privileged \
    -v /var/run/docker.sock:/host/var/run/docker.sock \
    -v /dev:/host/dev \
    -v /proc:/host/proc:ro \
    -v /boot:/host/boot:ro \
    -v /lib/modules:/host/lib/modules:ro \
    -v /usr:/host/usr:ro \
    -v /etc:/host/etc:ro \
    falcosecurity/falco:latest

Alternatively, you can use the eBPF probe driver:

docker pull falcosecurity/falco:latest
docker run --rm -i -t \
    --privileged \
    -v /var/run/docker.sock:/host/var/run/docker.sock \
    -v /proc:/host/proc:ro \
    -v /boot:/host/boot:ro \
    -v /lib/modules:/host/lib/modules:ro \
    -v /usr:/host/usr:ro \
    -v /etc:/host/etc:ro \
    falcosecurity/falco:latest -o engine.kind=ebpf

# Please remember to add '-v /sys/kernel/debug:/sys/kernel/debug:ro \' to the above docker command
# if you are running a kernel version < 4.14

It is also possible to use falco-no-driver and falco-driver-loader images in fully privileged mode. This may be desirable in environments which do not allow the full Falco image due to space, resource, security or policy constraints. You can load the eBPF probe or kernel module in its own temporary container as below:

docker pull falcosecurity/falco-driver-loader:latest
docker run --rm -i -t \
    --privileged \
    -v /dev:/host/dev \
    -v /proc:/host/proc:ro \
    -v /boot:/host/boot:ro \
    -v /lib/modules:/host/lib/modules:ro \
    -v /usr:/host/usr:ro \
    -v /etc:/host/etc:ro \
    falcosecurity/falco-driver-loader:latest

Once this has been done, or if you have installed the driver on the host permanently via the falcoctl driver tool instead of the Docker image, then you can simply load up the falco-no-driver image in privileged mode:

docker pull falcosecurity/falco-no-driver:latest
docker run --rm -i -t \
    --privileged \
    -v /var/run/docker.sock:/host/var/run/docker.sock \
    -v /dev:/host/dev \
    -v /proc:/host/proc:ro \
    -v /etc:/host/etc:ro \
    falcosecurity/falco-no-driver:latest

To use falco-no-driver and falco-driver-loader with the eBPF probe you have to remove the -v /dev:/host/dev (which is only required by the Kernel Module) and add:

    -v /root/.falco:/root/.falco \

Plus, adding -o engine.kind=ebpf as Falco command line option.

Other configurable options:

  • FALCOCTL_DRIVER_REPOS - See the Installing the driver section.
  • SKIP_DRIVER_LOADER - Set this environment variable to avoid running falcoctl driver tool when the falcosecurity/falco image starts. Useful when the driver has been already installed on the host by other means.

Modern eBPF

Privileged

The modern eBPF is bundled into Falco therefore the falco-no-driver image is enough. This allows you to run Falco without dependencies, just the following command:

docker run --rm -i -t \
           --privileged \
           -v /var/run/docker.sock:/host/var/run/docker.sock \
           -v /proc:/host/proc:ro \
           -v /etc:/host/etc:ro \
           falcosecurity/falco-no-driver:latest falco -o engine.kind=modern_ebpf

Least privileged

The following capabilities should be enough to run Falco with the Modern eBPF probe:

  • CAP_SYS_PTRACE
  • CAP_SYS_RESOURCE
  • CAP_BPF
  • CAP_PERFMON

Here we have the docker command to run with the modern probe.

docker run --rm -i -t \
           --cap-drop all \
           --cap-add sys_admin \
           --cap-add sys_resource \
           --cap-add sys_ptrace \
           -v /var/run/docker.sock:/host/var/run/docker.sock \
           -v /proc:/host/proc:ro \
           -v /etc:/host/etc:ro \
           falcosecurity/falco-no-driver:latest falco -o engine.kind=modern_ebpf

Note: in the command we use CAP_SYS_ADMIN because docker doesn't support CAP_BPF and CAP_PERFMON yet

Rules validation

It's possible to validate Falco rules without installation by using the Docker image.

export RULES_PATH=<PATH_TO_YOUR_RULES_HERE>
docker run --rm \
    -v ${RULES_PATH}:/etc/falco/my-rules \
    falcosecurity/falco:latest /usr/bin/falco \
    -r /etc/falco/falco_rules.yaml \
    -r /etc/falco/my-rules \
    -L

Hot Reload

This will reload the Falco configuration and restart the engine without killing the pid. This is useful to propagate new config changes without killing the daemon.

kill -1 $(cat /var/run/falco.pid)

Moreover, since Falco 0.32.0, watch_config_files config option drives the automatic reload of Falco when either the config or the ruleset change.