Cilium is a modern networking solution for container orchestration systems like Kubernetes, based on eBPF (extended Berkeley Packet Filter) technology. It enables efficient management of network traffic, security, and application-level observability. This article provides a step-by-step guide on how to set up and utilize Cilium on the CentOS 7 operating system, which is commonly used in enterprise server environments.
Prerequisites
- Installed and configured CentOS 7
- Root access or access with sudo privileges
- Installed Docker or another container runtime
Step 1: System Preparation
First, ensure that your system is up to date and has the necessary dependencies installed.
sudo yum update -y
sudo yum install -y epel-release
sudo yum install -y docker
sudo systemctl start docker && sudo systemctl enable docker
Step 2: Installing Cilium
Cilium can be installed directly on CentOS 7 using the Cilium CLI. First, install the Cilium CLI.
curl -L --remote-name-all https://github.com/cilium/cilium-cli/releases/latest/download/cilium-linux-amd64.tar.gz
tar xzvf cilium-linux-amd64.tar.gz
sudo mv cilium /usr/local/bin
After installing the CLI, you can initiate the installation of Cilium.
cilium install
Step 3: Configuring Cilium
After successful installation, configure Cilium to meet your specific requirements for network security and observability. Cilium allows detailed configuration through CiliumNetworkPolicy, which is a Kubernetes Custom Resource Definition (CRD) for defining network policies.
Below is an example of a simple network policy that blocks all inbound traffic to an application:
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
name: "deny-incoming"
spec:
endpointSelector:
matchLabels:
app: "myApp"
ingress:
- {}
Step 4: Using eBPF for Observability
eBPF is a key technology that Cilium leverages for observability and monitoring of network traffic. With eBPF, you can monitor the traffic flowing into and out of your applications without needing to modify the applications themselves.
Cilium provides tools such as cilium monitor and cilium bpf for real-time traffic monitoring and analysis.
cilium monitor --related-to=$(cilium endpoint list | grep 'myApp' | awk '{ print $1 }')
Step 5: Security Enforcement with Network Policies
In addition to observability, Cilium provides robust tools for securing your applications using network policies. For example, you can define policies that specify which services can communicate with each other and block all other traffic.
Cilium is a powerful tool for managing network security and observability at the application level, utilizing advanced eBPF capabilities. With this guide, you have walked through the process of setting up Cilium on CentOS 7, from system preparation to installation and configuration, to utilizing it for securing and monitoring your network environment. With Cilium and eBPF, you have powerful tools to enhance the security and visibility of your applications in modern Cloud environments.
