Kubernetes Ingress

Kubernetes Ingress is an API object that provides HTTP and HTTPS routing to services based on rules. It acts as an entry point for external traffic into the cluster, managing external access to services. Ingress allows you to define how external HTTP/S traffic should be processed and routed to different services within the cluster.

If you want to start with the beginning then you can click here

Key components and concepts of Kubernetes Ingress include:

1. Ingress Resource:

   - An Ingress resource is created to define the rules for how external HTTP/S traffic should be handled.

2. Rules:

   - Rules define how requests should be routed based on the host and path specified in the incoming request.

3. Backend Services:

   - Ingress directs traffic to backend services based on the defined rules.

4. TLS Termination:

   - Ingress can handle TLS termination, allowing you to configure HTTPS for your services.

5. Annotations:

   - Annotations provide additional configuration options, allowing you to customize Ingress behavior.

Example Ingress YAML:

```yaml

apiVersion: networking.k8s.io/v1

kind: Ingress

metadata:

  name: my-ingress

spec:

  rules:

    - host: example.com

      http:

        paths:

          - path: /app

            pathType: Prefix

            backend:

              service:

                name: app-service

                port:

                  number: 80

  tls:

    - hosts:

        - example.com

      secretName: tls-secret

```

In this example:

- Requests to `example.com/app` are directed to the `app-service`.

- TLS termination is configured using the secret `tls-secret` for HTTPS.

Key Benefits:

- Simplifies external access management.

- Allows centralized control of routing rules.

- Supports TLS termination for secure communication.

Kubernetes Ingress controllers (like NGINX Ingress Controller, Traefik, etc.) are responsible for implementing Ingress rules and managing traffic accordingly. The choice of Ingress controller may depend on specific requirements and features needed for your environment.

Kubernetes Ingress is similar to how a reverse proxy like NGINX works, but it operates at the Kubernetes cluster level. 

Ingress in Kubernetes is an API object that defines how external HTTP/S traffic should be processed and routed to different services within the Kubernetes cluster. The Ingress resource itself is just an abstraction. To make it effective, you need an Ingress controller, and NGINX is one of the popular choices for that.

Here's the breakdown:

1. Ingress Resource:

   - Defines the rules for routing external HTTP/S traffic to different services within the Kubernetes cluster.

2. Ingress Controller:

   - Actively watches for changes to Ingress resources.

   - Implements the rules defined in Ingress resources.

   - Manages the actual routing and traffic processing.

3. NGINX Ingress Controller:

   - One of the many available Ingress controllers for Kubernetes.

   - Implements Ingress rules using NGINX as a reverse proxy.

   - Handles the actual HTTP/S traffic based on the defined rules.

So, in a sense, you can think of Kubernetes Ingress working in conjunction with an Ingress controller like NGINX to manage external access and routing within your Kubernetes cluster.

How To Get the MongoDB Version from Another Docker Container

To get the MongoDB version from outside of MongoDB in the terminal, you can use the following commands:

Linux and macOS:

mongo --version

Windows:

mongod --version

These commands will print the version of MongoDB that is installed on your system.

For example, if you are running MongoDB version 5.0.13, the command will output the following:

MongoDB server version: 5.0.13

If you are running the MongoDB Compass GUI, you can also get the MongoDB version by clicking on the Help menu and selecting About MongoDB Compass.

There are a few ways to get the MongoDB version from another container when the MongoDB is running on a separate container and the other container is running a Debian-based image with Python:

1. Use the mongo command. You can use the mongo command to connect to the MongoDB container and get the version. To do this, you will need to know the IP address of the MongoDB container. You can get the IP address of the container using the docker inspect command.

docker inspect mongodb

Once you have the IP address of the MongoDB container, you can use the following command to connect to the container and get the version:

mongo --host <mongodb_container_ip_address> --version

2. Use the mongod command. You can also use the mongod command to get the version of MongoDB. To do this, you will need to know the port that MongoDB is running on. You can get the port that MongoDB is running on using the docker inspect command.

docker inspect mongodb

Once you have the port that MongoDB is running on, you can use the following command to get the version of MongoDB:

mongod --port <mongodb_container_port> --version

3. Use the Python MongoClient. You can also use the Python MongoClient to get the version of MongoDB. To do this, you will need to install the MongoClient package.

pip install pymongo

Once you have installed the MongoClient package, you can use the following code to get the version of MongoDB:

Python

import pymongo

client = pymongo.MongoClient('mongodb://<mongodb_container_ip_address>:<mongodb_container_port>')
db = client.test
print(db.version())

Which method you use to get the version of MongoDB depends on your specific needs and requirements.

Yes, it is possible to get the MongoDB version from another container using a shell script. Here is a simple example:

#!/bin/bash

# Get the IP address of the MongoDB container
mongodb_container_ip_address=$(docker inspect mongodb -f '{{.NetworkSettings.IPAddress}}')

# Get the version of MongoDB
mongodb_version=$(mongo --host $mongodb_container_ip_address --version)

# Print the version of MongoDB
echo "MongoDB version: $mongodb_version"

This shell script will first get the IP address of the MongoDB container using the docker inspect command. Then, it will use the mongo command to connect to the MongoDB container and get the version. Finally, it will print the version of MongoDB to the console.

You can save this shell script as a file, such as get_mongodb_version.sh, and then run it using the following command:

bash get_mongodb_version.sh

This will print the version of MongoDB to the console.

You can also use this shell script in other scripts or applications to get the version of MongoDB from another container. For example, you could use this shell script in a CI/CD pipeline to verify that the correct version of MongoDB is running before deploying your application.