Apache ZooKeeper VS k3os

Apache ZooKeeper — a distributed coordination, synchronization, and configuration service (written in Java);

To use Kafka, we also need to deploy a service that keeps configuration informations such as Zookeeper.

Failure Detection and Recovery It’s not enough to have backup systems. It’s also crucial to detect failures quickly. Modern systems employ monitoring tools and rely on distributed coordination systems such as Zookeeper or etcd to identify faults in real-time: once detected, recovery mechanisms are triggered to restore the service.

zookeeper: is (was?) used for secrets management. it was also used as a basic health check, but has been since been replaced.

You can install Kafka from https://kafka.apache.org/quickstart. Because Druid and Kafka both use Apache Zookeeper, I opted to use the Zookeeper deployment that comes with Druid, so didn’t start it with Kafka. Once running, I created two topics for me to post the data into, and for Druid to ingest from:

Please note that we use Zookeeper as the Governance Center.

Next, review deployment complexity such as DB-less versus database-backed deployments. For example, Kong does require running Cassandra or Postgres. Apigee requires Cassandra, Zookeeper, and Postgres to run, while other solutions like Express Gateway and Tyk only require Redis. Apache APISIX uses etcd as its data store, it stores and manages routing-related and plugin-related configurations in etcd in the Data Plane.

ZooKeeper, a system for coordinating distributed nodes, similar to Google's Chubby

[Unit] Description=Apache Zookeeper server Documentation=http://zookeeper.apache.org Requires=network.target remote-fs.target After=network.target remote-fs.target [Service] Type=simple ExecStart=/usr/local/kafka/bin/zookeeper-server-start.sh /usr/local/kafka/config/zookeeper.properties ExecStop=/usr/local/kafka/bin/zookeeper-server-stop.sh Restart=on-abnormal [Install] WantedBy=multi-user.target

ElasticJob achieves distributed coordination through ZooKeeper. In practical scenarios, users may start multiple jobs in the same project simultaneously, all of which use the same Apache Curator client. There are certain risks due to the nature of ZooKeeper and the callback method of Curator in a single event thread.

I still don't forgive SUSE for buying Rancher and then unceremoniously killing k3os. They just left the website up and everything, made no announcement, made no attempt to help the community take over, just left the Github repo to rot: https://k3os.io/

Hard to have confidence in SUSE's commitment to another open source operating system side project after that. SUSE's announcement at the time:

Like SUSE, Rancher is 100% open source and equally as passionate as SUSE about true open source innovation, community empowerment, and customer success. SUSE and Rancher share the same goal – happy and satisfied customers.

https://www.suse.com/c/suse-acquires-rancher/

k3os is no longer supported by Rancher: https://github.com/rancher/k3os/issues/846 I've been keeping mine up to date with https://github.com/BlueKrypto/k3os

[0] https://docs.k3s.io/installation/ha-embedded [1] https://k3os.io/

I (still) run k3os, but it's dead since SUSE bought rancher. (see https://github.com/rancher/k3os/issues/846)

virt-install --install \ --memory 2048 \ --os-type linux \ --os-variant ubuntu20.04 \ --disk size=20 \ --graphics=none \ --name k3os \ kernel=https://github.com/rancher/k3os/releases/download/v0.21.5-k3s2r1/k3os-vmlinuz-amd64,initrd=https://github.com/rancher/k3os/releases/download/v0.21.5-k3s2r1/k3os-initrd-amd64,kernel_args='k3os.fallback_mode=install k3os.install.iso_url=https://github.com/rancher/k3os/releases/download/v0.21.5-k3s2r1/k3os-amd64.iso k3os.install.silent=true k3os.install.tty=ttyS0 console=ttyS0 k3os.install.device=/dev/vda k3os.password=hunter2'

I'm personally fond of https://k3os.io for my small to medium hobby and professional clusters. It comes with a lot the bells and whistles, but is also pretty minimum and just scales easily.

I really liked K3OS, but I feel like Rancher is no longer supporting it. The last commit on the k3os repo is from April, and before those three commits, November of last year. When Rancher decided to move their HCI offering, Harvester, over to RancherOS V2 being based on cOS toolkit/OpenSuse, I don't have high hopes that K3OS will be maintained.

I run k3os on an old laptop with a broken screen.