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refactor instructions
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- More instructions re: Cilium components
- Add information to give out while connectivity test is ongoing
- Bundle Hubble Relay and Hubble UI enable (no double reconfiguration)
- Various small touchups + typos

Signed-off-by: Nicolas Busseneau <[email protected]>
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Expand Up @@ -20,10 +20,17 @@ And listing the pods in the cluster:
kubectl get pods -A
```

Note that the `coredns` pod is stuck in `ContainerCreating`: this is normal as our cluster does not have any CNI installed for now.
Depending on your local environment and Minikube version, a CNI might or might not have been installed automatically by Minikube.
Ideally, no CNI has been installed and you will see the `coredns` pod stuck in `ContainerCreating`.
However we can continue even if a CNI has been installed and `coredns` has already started, as the installation will override the CNI and restart unmanaged pods.

# Cilium

Documentation:

- https://docs.cilium.io/en/stable/concepts/overview/
- https://docs.cilium.io/en/stable/gettingstarted/

We will start by installing the `cilium` CLI and then installing Cilium in our cluster.

## Install Cilium CLI
Expand Down Expand Up @@ -61,6 +68,8 @@ cilium status
cilium install --help
```

As we can see, `cilium install` offers various configurations knobs that can be leveraged to tweak Cilium to our needs.

## Install Cilium in the Minikube cluster

Install Cilium:
Expand All @@ -69,27 +78,49 @@ Install Cilium:
cilium install
```

Then verify the installation:
In this example we use the default configuration: note how `cilium install` automatically chooses a default configuration based on the detected environment.
As suggested, we then verify the installation:

```sh
cilium status
```

Note how `cilium status` is reporting information on both:

- Cilium Agents, which run on each node in the cluster (scheduled via `DaemonSet`) and are responsible for the actual operations (managing eBPF programs for pod networking).
- Cilium Operator, which is responsible for cluster-wide operations such as IPAM or `kvstore` operations (scheduled via `Deployment`).

Take a look at the pods again to see what happened under the hood:

```sh
kubectl get pods -A
```

Cilium is now properly installed and manages connectivity within the cluster, allowing `coredns` to start properly.
The Cilium pods as shown in `cilium status` have been added to the `kube-system` namespace.

We can verify connectivity by running a connectivity test (which will be deployed in namespace `cilium-test`):
Also note that the Cilium configuration is stored in a ConfigMap:

```sh
kubectl get cm cilium-config -o yaml -n kube-system
```

Cilium is now properly installed and manages connectivity within the cluster.

We can verify connectivity by running a connectivity test:

```sh
cilium connectivity test
```

Once done, clean up the connectivity test namespace:
This will deploy test pods in the `cilium-test` namespace and go through our CLI's test suite.
The test suite is designed as a complementary check to `cilium status`, verifying that Cilium is correctly handling connectivity in various scenarios (e.g. with and without network policies).
It's explicitly intended to be run on any cluster any time you want to check Cilium is working properly: it auto-detects the environment/configuration and automatically chooses which tests to run.

Since the test takes a little while to run, an additional information: Cilium can be installed via the CLI as we just did, or via Helm if better suited to your use case (see our documentation: https://docs.cilium.io/en/stable/gettingstarted/k8s-install-helm/).

No matter how Cilium was installed (CLI or Helm), you can always use the Cilium CLI to interact with Cilium: we definitely recommend you to run `cilium connectivity test` at least once after any Cilium install.

Once done with the connectivity test, clean up the test namespace:

```sh
kubectl delete ns cilium-test --wait=false
Expand Down Expand Up @@ -152,15 +183,15 @@ We can do it by crafting a new network policy manually, but we can also use the

- Go to https://networkpolicy.io/editor.
- Upload our initial `backend-ingress-deny` policy.
- Rename the network policy to `backend-allow-ingress-frontend` (using the `Edit` button in the center).
- On the ingress side, add `app=frontend` as `podSelector` for pods in the same namespace.
- Rename the network policy to `backend-ingress-allow-frontend` (using the **Edit** button in the center).
- On the ingress side **In Namespace** on the left, add a **pod selector** rule with expression `app=frontend`.
- Inspect the ingress flow colors: the policy will deny all ingress traffic to pods labelled `app=backend`, except for traffic coming from pods labelled `app=frontend`.
- Download the policy YAML file.

Apply the new policy and check that connectivity has been restored, but only from the frontend:

```sh
kubectl create -f backend-allow-ingress-frontend.yaml
kubectl create -f backend-ingress-allow-frontend.yaml
kubectl exec -ti ${FRONTEND} -- curl -I --connect-timeout 5 backend:8080 | head -1
kubectl exec -ti ${NOT_FRONTEND} -- curl -I --connect-timeout 5 backend:8080 | head -1
```
Expand Down Expand Up @@ -216,8 +247,17 @@ In a real world scenario, cluster administrators may leverage network policies a

# Hubble

By default, Cilium acts only as a CNI and is thus mostly responsible for networking, though it can help a bit with security (e.g. advanced network policies).
To take full advantage of eBPF deep observability and security capabilities, we must enable the optional Hubble component (which is disabled by default).
Documentation:

- https://docs.cilium.io/en/stable/gettingstarted/hubble_setup/
- https://docs.cilium.io/en/stable/gettingstarted/hubble_cli/
- https://docs.cilium.io/en/stable/gettingstarted/hubble/

Hubble offers deep observability capabilities thanks to eBPF, but by default is only exposed locally via gRPC from the Cilium Agents.
For convenience, Cilium offers optional components to allow accessing Hubble data in a user-friendly way:

- Hubble Relay: provides cluster-wide observability via the Hubble CLI.
- Hubble UI: user-friendly web UI (requires Hubble Relay).

## Install the Hubble CLI

Expand Down Expand Up @@ -257,26 +297,36 @@ hubble observe --help

## Enable Hubble in Cilium

Enable the optional Hubble component:
We can use the Cilium CLI to reconfigure Cilium and enable Hubble:

```sh
cilium hubble enable
cilium hubble enable --ui
```

Take a look at the pods again to see what happened under the hood:
Note the optional `--ui` flag to enable both the required Hubble Relay component which we will showcase first, and the optional Hubble UI component which we will showcase afterwards.

Take a look at the pods and ConfigMaps again to see what happened under the hood:

```sh
kubectl get pods -A
kubectl get cm -n kube-system
```

Cilium agents are restarting, and a new Hubble Relay pod is now present.
With the reconfiguration:

- New Hubble pods for both components have been added to the `kube-system` namespace.
- The `cilium-config` ConfigMap has been updated.
- New Hubble ConfigMaps for both components have been added.

We can wait for Cilium and Hubble to be ready by running:

```sh
cilium status --wait
```

Once ready, we can locally port-forward to the Hubble pod:
Note that `cilium status` now displays additional information regarding Hubble components.

Once ready, we can locally port-forward to Hubble Relay:

```sh
cilium hubble port-forward&
Expand Down Expand Up @@ -322,41 +372,7 @@ This is really handy when developing / debugging network policies.

## Hubble UI

Not only does Hubble allow to inspect flows from the command line, it also allows us to see them in real time on a graphical service map via Hubble UI.
Again, this also is an optional component that is disabled by default.

Enable the optional Hubble UI component:

```sh
cilium hubble enable --ui
```

Take a look at the pods again to see what happened under the hood:

```sh
kubectl get pods -A
```

Cilium agents are restarting, and a new Hubble UI pod is now present on top of the Hubble Relay pod.
As above, we can wait for Cilium and Hubble to be ready by running:

```sh
cilium status --wait
```

And then check Hubble status:

```
hubble status
```

> Note: our earlier `cilium hubble port-forward` should still be running (can be checked by running `jobs` or `ps aux | grep "cilium hubble port-forward"`).
> If it does not, `hubble status` will fail and we have to run it again:
>
> ```sh
> cilium hubble port-forward&
> hubble status
> ```
Since we enabled the additional Hubble UI component, not only can we inspect flows from the command line, we can also see them in real time on a graphical service map.

To start Hubble UI:

Expand All @@ -365,31 +381,26 @@ cilium hubble ui
```

The browser should automatically open http://localhost:12000/ (open it manually if not).
We can then access the graphical service map by selecting our `default` namespace, and generating some network activity again:

```sh
for i in {1..10}; do
kubectl exec -ti ${FRONTEND} -- curl -I --connect-timeout 5 backend:8080
kubectl exec -ti ${NOT_FRONTEND} -- curl -I --connect-timeout 5 backend:8080
done
```
We can then access the graphical service map by selecting a namespace.

Hubble flows are displayed in real time at the bottom, with a visualization of the namespace objects in the center.
Click on any flow, and click on any property from the right side panel: notice that the filters at the top of the UI have been updated accordingly.

Let's run a connectivity test again and see what happens in Hubble UI in the `cilium-test` namespace:
In this example, we will generate some network activity by running a connectivity test in a separate terminal:

```sh
cilium connectivity test
```

We can see that Hubble UI is not only capable of displaying flows within a namespace, it also helps visualizing flows going in or out.
The `cilium-test` namespace should now be available from Hubble UI.

Hubble flows (identical to those from `hubble observe`) are displayed in real time at the bottom, with a visualization of the namespace objects in the center.
Click on any flow, and click on any property from the right side panel: notice that the filters at the top of the UI have been updated accordingly.

After some time, the connectivity test will run tests reaching out to the outside world: Hubble observes not only flows within our cluster but also flows going in or out.

# Conclusion

In this Installfest, we have used Cilium and Hubble CLIs to install Cilium in a Kubernetes cluster, and then manipulated Network Policies and Hubble.
We are not going to showcase them in this demo, but Cilium supports many more features.
To highlight some of them which you might want to explore as a next step building upon the knowledge gained during this Installfest:
To highlight some which you might want to explore next:

## Encryption

Expand All @@ -410,13 +421,19 @@ Documentation:
- https://docs.cilium.io/en/stable/gettingstarted/clustermesh/clustermesh/
- https://docs.cilium.io/en/stable/gettingstarted/external-workloads/

Cilium support meshing together multiple clusters or connecting non-Kubernetes workloads (e.g. VMs) to a Kubernetes cluster.
Cilium supports meshing together multiple clusters or connecting non-Kubernetes workloads (e.g. VMs) to a Kubernetes cluster.
Akin to Hubble, clustermesh capabilities are an optional component managed from the Cilium CLI:

```sh
cilium clustermesh --help
```

## Slack

Thank you for following the Installfest :)
If you have any questions or topics you'd like to discuss, now is a good time.
You are also most welcome to join our Slack at https://cilium.herokuapp.com/.

# Clean up

Documentation: https://minikube.sigs.k8s.io/docs/commands/delete/
Expand Down

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