Container Management¶

NITA uses containers for all of its application components. This page covers how to manage, inspect, and customize containers.

Container Types¶

graph TB
    subgraph "Persistent Containers"
        JEN["Jenkins<br/>juniper/nita-jenkins:23.12-1"]
        WEB["Webapp<br/>juniper/nita-webapp:25.10-1"]
        DB["MariaDB<br/>mariadb:10.4.12"]
        PROXY["Nginx<br/>nginx:stable"]
    end

    subgraph "Ephemeral Containers"
        ANS["Ansible<br/>juniper/nita-ansible:22.8-1"]
        ROB["Robot<br/>juniper/nita-robot:22.8-1"]
    end

    JEN -.->|"Launches"| ANS
    JEN -.->|"Launches"| ROB

Inspecting Containers¶

With nita-cmd¶

# List running NITA containers
nita-cmd containers ls

# Show container versions
nita-cmd containers versions

# Show container IP addresses
nita-cmd ips

# Show container resource usage
nita-cmd stats

With kubectl¶

# List pods (containers)
kubectl get pods -n nita

# Describe a specific pod
kubectl describe pod <pod-name> -n nita

# View container logs
kubectl logs <pod-name> -n nita

Accessing Container Shells¶

NITA Containers¶

# Jenkins (as jenkins user)
nita-cmd jenkins cli jenkins

# Jenkins (as root)
nita-cmd jenkins cli root

# Webapp
nita-cmd webapp cli

# Ansible (starts ephemeral container)
nita-cmd ansible cli 22.8

# Robot (starts ephemeral container)
nita-cmd robot cli 22.8

Standard Containers (MariaDB, Nginx)¶

Standard containers are not tagged as NITA, so use kubectl:

# Find the pod name
kubectl get pods -n nita

# Access the shell
kubectl exec -it -n nita <pod-name> -- bash

Ephemeral Container Behaviour¶

• Launched by Jenkins as Kubernetes jobs
• Mount shared volumes: /project and /var/tmp/build
• Only one instance can run at a time
• Data is temporary — reset on each execution
• Auto-deleted 2 minutes after completion

Creating Custom Containers¶

You can customize any NITA container by modifying its Dockerfile and rebuilding.

Prerequisites¶

Install Docker Community Edition:

sudo dnf install -y docker-ce
sudo usermod -aG docker <username>
sudo service docker restart

sudo apt install -y docker-ce
sudo usermod -aG docker <username>
sudo service docker restart

Example: Custom Jenkins Container¶

1. Replace the Dockerfile:

cd /opt/nita-jenkins
sudo mv Dockerfile Dockerfile-
sudo wget https://github.com/Juniper/nita/raw/refs/heads/main/examples/chatgpt/robot.jar
sudo wget https://raw.githubusercontent.com/Juniper/nita/refs/heads/main/examples/chatgpt/Dockerfile

2. Update the build tag in build_container.sh:

docker build --build-arg KUBECTL_ARCH=${KUBECTL_ARCH} -t juniper/nita-jenkins:25.01-1 .

3. Build the image:

sudo ./build_container.sh

4. Verify the image:

docker image ls
# REPOSITORY             TAG       IMAGE ID       CREATED         SIZE
# juniper/nita-jenkins   25.01-1   79300ab8d042   8 minutes ago   1.69GB

5. Import into containerd:

docker save juniper/nita-jenkins:25.01-1 > nita-jenkins:25.01-1.tar
sudo ctr -n=k8s.io image import nita-jenkins:25.01-1.tar

6. Update the Kubernetes deployment:

Edit /opt/nita/k8s/jenkins-deployment.yaml:

# Change:
image: juniper/nita-jenkins:23.12-1
# To:
image: juniper/nita-jenkins:25.01-1

7. Restart the pod:

sudo kubectl delete deployment jenkins -n nita
sudo kubectl apply -f /opt/nita/k8s/jenkins-deployment.yaml
sudo systemctl restart kubelet

If Kubernetes uses the cached image:

sudo kubectl rollout restart deployment/jenkins -n nita

Custom Container Workflow¶

graph TD
    A["Modify Dockerfile"] --> B["Build with Docker"]
    B --> C["Save as .tar"]
    C --> D["Import into containerd"]
    D --> E["Update K8s deployment YAML"]
    E --> F["Delete & re-apply deployment"]
    F --> G["New pod with custom image"]

    style A fill:#1565C0,color:#fff
    style G fill:#2E7D32,color:#fff