The lighty.io RESTCONF-NETCONF (RNC) application allows to easily initialize, start and utilize the most used OpenDaylight services, including clustering and optionally add custom business logic. PANTHEON.tech provides a pre-prepared Helm chart inside the lighty.io RNC application, which can be easily used for Kubernetes deployment.

Clustering is a mechanism that enables multiple processes and programs to work together as one entity.

For example, when you search for something on google.com, it may seem like your search request is processed by only one web server. In reality, your search request is processed by many web servers connected in a cluster. Similarly, you can have multiple instances of OpenDaylight working together as one entity.

The advantages of clustering are:

• Scaling: If you have multiple instances of OpenDaylight running, you can potentially do more work and store more data than you could with only one instance. You can also break up your data into smaller chunks (shards) and either distribute that data across the cluster or perform certain operations on certain members of the cluster.
• High Availability: If you have multiple instances of OpenDaylight running and one of them crashes, you will still have the other instances working and available.
• Data Persistence: You will not lose any data stored in OpenDaylight after a manual restart or a crash.

This article demonstrates, how to configure the lighty.io RNC application to use clustering, rescaling of the cluster and connecting a device to the cluster.

Add the PANTHEON.tech Helm Repository to MicroK8

For deploying the lighty.io RNC application, we will use and show how to install the microk8s Local Kubernetes engine. Feel free to use any other of your favorite local Kubernetes engines, which you have installed.

1. Install microk8s with snap.

sudo snap install microk8s --classic
sudo usermod -a -G microk8s $USER
sudo chown -f -R $USER ~/.kube

2. Enable the required add-ons.

microk8s enable dns helm3

3. Add the PANTHEON.tech Helm repository to microk8s.

microk8s.helm3 repo add pantheon-helm-repo https://pantheontech.github.io/helm-charts/

microk8s.helm3 repo update

microk8s.helm3 install lighty-rnc-app pantheon-helm-repo/lighty-rnc-app-helm --version 16.1.0 --set lighty.replicaCount=3,lighty.akka.isSingleNode=false,nodePort.useNodePort=false,lighty.moduleTimeOut=120

microk8s.helm3 ls

image:
  name: ghcr.io/pantheontech/lighty-rnc
  version: 16.1.0
  pullPolicy: IfNotPresent

microk8s.helm3 install lighty-rnc-app pantheon-helm-repo/lighty-rnc-app-helm --version 16.1.0 --values [VALUES_YAML_FILE]

microk8s.kubectl get pods

sudo docker build -t lighty-netconf-simulator .

sudo docker run -d --rm --name netconf-simulator -p17830:17830 lighty-netconf-simulator:latest

docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' netconf-simulator

microk8s.kubectl get pods -l app.kubernetes.io/name=lighty-rnc-app-helm -o custom-columns=":status.podIP"

curl  --request GET 'http://[HOST_IP]:8558/cluster/members/'

{
    "leader": "akka://opendaylight-cluster-data@10.1.101.177:2552",
    "members": [
        {
            "node": "akka://opendaylight-cluster-data@10.1.101.177:2552",
            "nodeUid": "4687308041747729846",
            "roles": [
                "member-10.1.101.177",
                "dc-default"
            ],
            "status": "Up"
        },
        {
            "node": "akka://opendaylight-cluster-data@10.1.101.178:2552",
            "nodeUid": "-29348997399314594",
            "roles": [
                "member-10.1.101.178",
                "dc-default"
            ],
            "status": "Up"
        }
    ],
    "oldest": "akka://opendaylight-cluster-data@10.1.101.177:2552",
    "oldestPerRole": {
        "member-10.1.101.177": "akka://opendaylight-cluster-data@10.1.101.177:2552",
        "dc-default": "akka://opendaylight-cluster-data@10.1.101.177:2552",
        "member-10.1.101.178": "akka://opendaylight-cluster-data@10.1.101.178:2552"
    },
    "selfNode": "akka://opendaylight-cluster-data@10.1.101.177:2552",
    "unreachable": []
}

curl --request PUT 'http://[HOST_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf/node=new-node' \
--header 'Content-Type: application/json' \
--data-raw '{
    "netconf-topology:node": [
        {
            "node-id": "new-node",
            "host": [DEVICE_IP],
            "port": 17830,
            "username": "admin",
            "password": "admin",
            "tcp-only": false,
            "keepalive-delay": 0
        }
    ]
}

curl --request GET 'http://[MEMBER_1_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf/node=new-node'
curl --request GET 'http://[MEMBER_2_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf/node=new-node'
...

{
    "network-topology:node": [
        {
            "node-id": "new-node",
            "netconf-node-topology:connection-status": "connected",
            "netconf-node-topology:username": "admin",
            "netconf-node-topology:password": "admin",
            "netconf-node-topology:available-capabilities": {
                "available-capability": [
                    {
                        "capability": "urn:ietf:params:netconf:base:1.1",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "urn:ietf:params:netconf:capability:notification:1.0",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "urn:ietf:params:netconf:capability:candidate:1.0",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "urn:ietf:params:netconf:base:1.0",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:ietf:params:xml:ns:yang:ietf-inet-types?revision=2013-07-15)ietf-inet-types",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:opendaylight:yang:extension:yang-ext?revision=2013-07-09)yang-ext",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:tech.pantheon.netconfdevice.network.topology.rpcs?revision=2018-03-20)network-topology-rpcs",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:ietf:params:xml:ns:yang:ietf-yang-types?revision=2013-07-15)ietf-yang-types",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:TBD:params:xml:ns:yang:network-topology?revision=2013-10-21)network-topology",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring?revision=2010-10-04)ietf-netconf-monitoring",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:opendaylight:netconf-node-optional?revision=2019-06-14)netconf-node-optional",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:ietf:params:xml:ns:netconf:notification:1.0?revision=2008-07-14)notifications",
                        "capability-origin": "device-advertised"
                    },
                    {
                        "capability": "(urn:opendaylight:netconf-node-topology?revision=2015-01-14)netconf-node-topology",
                        "capability-origin": "device-advertised"
                    }
                ]
            },
            "netconf-node-topology:host": "172.17.0.2",
            "netconf-node-topology:port": 17830,
            "netconf-node-topology:tcp-only": false,
            "netconf-node-topology:keepalive-delay": 0
        }
    ]
}

microk8s.kubectl get pods

microk8s.kubectl get pod [NAME] -o custom-columns=":status.podIP" | xargs

microk8s.kubectl delete -n default pod [LEADER_NAME]

microk8s.kubectl get pods

6. Verify, that a new leader was elected

curl  --request GET 'http://[HOST_IP]:8558/cluster/members/'

{
    "leader": "akka://opendaylight-cluster-data@10.1.101.178:2552",
    "members": [
        {
...

As a result of deleting the pod, a new leader was elected from the previous pods.

7. Verify that the new pod also contains the device. The response should be the same as in step 4.

curl --request GET 'http://[NEW_MEMBER_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf/node=new-node'

8. Delete the device

curl --request DELETE 'http://[HOST_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf/node=new-node'

9. Verify that the testing device was removed from all cluster members

curl --request GET 'http://[MEMBER_1_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf'
curl --request GET 'http://[MEMBER_1_IP]:8888/restconf/data/network-topology:network-topology/topology=topology-netconf'
...

Your response should look like this:

{
    "network-topology:topology": [
        {
            "topology-id": "topology-netconf"
        }
    ]
}

10. Logs from the device can be shown by executing this command:

sudo docker logs [CONTAINER ID]

11. Logs from the lighty.io RNC app can be shown by executing the following command:

microk8s.kubectl logs [POD_NAME]

This post explained how to start a containerized, lighty.io RNC application and configure it to use clustering. Furthermore, an explanation of how to make your own cluster configuration either from a file or using –set flag was shown, to set the size of the cluster to your liking.  Rescaling of the cluster and connecting a simulator device to the cluster was also shown and explained.

by Tobiáš Pobočík & Peter Šuňa | Leave us your feedback on this post!

You can contact us here.

Explore our PANTHEON.tech GitHub.

Watch our YouTube Channel.

PANTHEON.tech is an avid open-source supporter. As the largest contributor to the OpenDaylight source-code, as well as being active in many more open-source projects and creating our own, we believe that open software is a way of enriching collaboration and making better products overall.

Open-source is also a philosophy of freedom, meaningfulness, and the idea that wisdom should be shared.

Practical consequences of software being open are far-reaching and have great significance – much bigger than an uninvolved observer would guess at a first glance. To see the consequences, you need to take a look at a big enough project. Or even better, at an entire infrastructure, consisting of open-source projects.

Collaboration in Open-Source

A big advantage open-source brings is collaboration. This might sound obvious, but it has several forms:

• The collaboration between companies, even competitors, contributing their own piece to the common open code, results in multiple-times better products, compared to standalone work.
• The collaboration of academics. The best results were always done with academic precision.

Research & Academics in Open-Source

Researchers prefer to spend their valuable time working on open code and open research. Some run their state-of-art static or formal analysis tools as part of their research upon open-source projects and then send patches.

Some design well-defined APIs, as for example UNIX POSIX. Others solve known problems using open-source platforms as a base, for example, NixOS, which solves so many problems with packaging.

But why do academics prefer open code? Not only because open code is more accessible. Some of them prefer open code, due to a philosophical point of view – since a code is similar to a mathematical equation or other scientific findings, it should be published publically.

A code should be perfect, consistent, and bug-free. That’s why collaboration with people having this mindset is invaluable.

Community & Collaboration

Community collaboration. There is no small amount of excellent engineers contributing to open-source in their free time either for fun, own needs, belief in open source philosophy, or to help other people and seeking sense in their work.

Informal collaboration – mailing lists, IRC channels, Stack Overflow, blogs, and forums. Everyone who developed a closed-sourced project knows what I am talking about. How much easier is it to find needed information about an open-source project, whether it is a guide, documentation, explanation of error message, or bug.

This makes work on open-source projects much more effective and simple.

Verification in Open-Source

The verification side of collaboration is crucial. The amount of eyeballs controlling your code, again and again, is a huge advantage, compared to the closed-source way of a one or two-person, one-time review. For the same reason, Linus Torvalds said:

I made it publicly available but I had no intention to use the open-source methodology, I just wanted to have comments on the work.

Different people have different ideas and points of view. The involvement of lots of computer science experts makes the results far more promising and objective.

The overall time diverse people spend working on open-source is much bigger than the costs any corporation would be willing to pay for their closed source equivalent.

But there is much more about open source than just better collaboration. Open-source is also a philosophy of freedom, meaningfulness, and the idea that wisdom should be shared.

People would rather create something that makes sense and that might help other people, as we are social beings. Also, using something without the necessity of being bound in any way.

Imagine a Closed World

Now, just for contradiction, let’s imagine everything was closed – even standards and protocols in one big monopoly.

You would be forced to use only their technology, to buy services or updates to be able to work as usual. And what’s worse? What if the company stops to deliver or support something, you really need? For example, formatting of your important documents.

Kind of scary. Let’s rather imagine an open world, where absolutely everything is done in an open-source manner, even cars, electrical appliances, everything. I believe that now you got the importance of open-source philosophy as well.

Open source is the future. It’s modern, and it’s the right way to go from many points of view. Even big players who initially didn’t like the idea are now involved, at least partially.

But how can we adapt to these changes? How it is possible to be in business with open-source?

Stay tuned for Part 2, where we might touch on this topic.

by Július Milan | Leave us your feedback on this post!

You can contact us here.

Explore our PANTHEON.tech GitHub.

Watch our YouTube Channel.