docker-swarm-autoscaler VS etcd

If you want to have some sort of auto scaling, you will need to monitor to some extent though as this will be the signal for scaling up/down. I noticed that https://github.com/jcwimer/docker-swarm-autoscaler already includes the relevant prometheus configs required for just scaling by cpu.

Nomad, Docker Swarm and other solutions support most of these out of the box, Kubernetes is just the most popular and flexible (with which comes a lot of complexity) solution, it seems.

For example, even something as basic as Docker Swarm will see you a lot of the way through.

> How do you implement healthcheck?

Supported by Docker: https://docs.docker.com/engine/reference/builder/#healthchec...

> Does the loadbalancer know how the healthceck is implemented?

When the health checks pass in accordance with the above config, the container state will change from "starting" to "healthy" and traffic will be able to be routed to it. Until then you can have a web server or whatever show a different page/implement circuit breaking or whatever.

> How do you determine it's time to scale?

Docker Swarm doesn't have an abstraction for autoscaling, though there are a few community projects. One can feasibly even write something like that themselves in an evening: https://github.com/jcwimer/docker-swarm-autoscaler

That said, I mostly ignore this concern because I'm yet to see a workload that needs to dynamically scale in any number of private or government projects that I've worked on. Most of the time people want predictable infrastructure and being able to deal with backpressure (e.g. message queue), though that's different with startups.

> How do you implement always-on-process? service unit, initd, cron?

The service abstraction comes out of the box: https://docs.docker.com/engine/swarm/how-swarm-mode-works/se...

You might also want to decide how to best schedule it: wherever available, on a particular node (hostname/tag/...) or on all nodes, which is actually what Portainer agent does! Example: https://docs.portainer.io/start/install/server/swarm/linux

> How do you export the logs?

Docker supports multiple logging drivers: https://docs.docker.com/config/containers/logging/configure/

> How do you inject configs? /etc/environment, profile.d, systemd config, /etc/bestestapp/config?

Docker and Compose/Swarm support environment variables: https://docs.docker.com/compose/compose-file/#environment

If you need config files, you can also use bind mounts: https://docs.docker.com/storage/bind-mounts/

> What about secrets?

Docker supports secrets out of the box: https://docs.docker.com/engine/swarm/secrets/

> Service discovery? Is unbound/bind9?

Docker Swarm supports built in DNS, even allows for multiple separate networks: https://docs.docker.com/engine/swarm/networking/

> These items are best done in a standard way.

Agreed! Though I'd say that the only two options being "running everything on *nix directly" and "running everything in Kubernetes" is a false narrative! The former can work but can also lead to non-standard and error-prone environments with a horrible waste of human resources, whereas the latter can work but can also lead to overcomplicated and hard to debug environments with a horrible waste of human resources.

The best path for many folk probably lies somewhere in the middle, with Nomad/Swarm/Compose/Docker, regardless of what others might claim. The best path for folks interested in a DevOps career is probably running on cloud managed Kubernetes clusters and just using their APIs to lots of great results, not caring about how expensive that is or how easy it would be to self-host on-prem.

sudo dnf -y install curl wget vim ETCD_RELEASE=$(curl -s https://api.github.com/repos/etcd-io/etcd/releases/latest|grep tag_name | cut -d '"' -f 4) echo $ETCD_RELEASE wget https://github.com/etcd-io/etcd/releases/download/${ETCD_RELEASE}/etcd-${ETCD_RELEASE}-linux-amd64.tar.gz tar xvf etcd-${ETCD_RELEASE}-linux-amd64.tar.gz cd etcd-${ETCD_RELEASE}-linux-amd64 sudo mv etcd* /usr/local/bin ls /usr/local/bin /usr/local/bin/etcd --version

Reading the standard library will give you ideas/insight about various Go idiomatic patterns/approaches, and you can see a full website/API implementation in the pkg.go.dev repository (https://github.com/golang/pkgsite). Projects like https://github.com/etcd-io/etcd may be interesting too.

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.

Service Discovery: Microservices need to discover and communicate with each other dynamically. Service discovery tools like etcd, Consul, or Kubernetes built-in service discovery mechanisms help locate and connect to microservices running on different nodes within the infrastructure.

APISIX uses etcd to store and synchronize configurations.

etcd is an excellent key-value distributed database used internally by Kubernetes and managed by the CNCF. It's a great option, and that's the reason why Apache APISIX uses it too. Yet, it's not devoid of issues.

Someone on HN (https://news.ycombinator.com/item?id=36682595) suggested etcd (https://etcd.io)

In traditional mode, APISIX stores its configuration in etcd. APISIX offers a rich API to access and update the configuration, the Admin API. In standalone mode, the configuration is just plain YAML. It's the approach for GitOps practitioners: you'd store your configuration in a Git repo, watch it via your favorite tool (e.g., Argo CD or Tekton), and the latter would propagate the changes to APISIX nodes upon changes. APISIX reloads its configuration every second or so.

I am not sure neither. But this might overcome the etcd's soft storage limit of 8GB? [1]

[1] https://github.com/etcd-io/etcd/issues/9771