Understanding ReplicaSet vs. StatefulSet vs. DaemonSet vs. Deployments
60 points by Abhisman 6 days ago | 25 comments
  • ofrzeta 5 days ago |
    Doesn't seem to offer more insights than the Kubernetes docs.
    • LetMeLogin 5 days ago |
      Totally. Plus it's misguiding readers with different functionality and use cases.

      For example "Persistent Storage: StatefulSets provide persistent storage to their pods through Kubernetes PersistentVolumes".

      The thing is that STS doesn't do that. That's actually in POD definition.

      • MuffinFlavored 5 days ago |
        I had no idea... probably shows I haven't hit an advanced enough use case.

        > why isn't a statefulset just a deployment/pod with PVC mounted?

        * StatefulSets provide predictable pod names and hostnames (pod-0, pod-1)

        * StatefulSets handle pods sequentially (0→1→2), ensuring proper cluster initialization.

        * StatefulSets maintain a consistent pod-to-PVC mapping even after pod rescheduling.

        * StatefulSets delete pods in reverse order,

        • wbl 5 days ago |
          You can look at the structure in TFA to see this. The only discussion of the volume mounting is in the pod template, not the Stateful Set itself.
        • vanillax 5 days ago |
          You can map a PVC back to a pod without statefulset. You just need to create the PV and PVC and map it to a deployment.
      • sitkack 5 days ago |
        "Come on!"
      • vanillax 5 days ago |
        Agree. Its more confusion. PVC / PV are native to k8s not something part of statefulsets. In fact you _probably_ only need to use Statefulsets for databases. Which is probably going to be abstracted away with Operators.
        • verdverm 4 days ago |
          It's more about roll forward/backward and services with a master+replica or leader election. That PVCs are common in stateful sets is more a symptom than the cause
          • vanillax 4 days ago |
            Yea for sure. Thats why I dropped the term database because thats the exact scenario ( master / replica ) where pod consistency naming,dns, network etc is important for StatefulSet.
      • null0pointer 4 days ago |
        Author is most likely farming credibility with blog spam.
    • Abhisman a day ago |
      "Maybe readers would want to read what I've written" - That's the approach that I had in mind when writing the article.
  • kevmo314 5 days ago |
    > Understanding the nuances and distinctions between these key concepts becomes crucial as you navigate the complex — yet rewarding — waters of container orchestration.

    Can't say I've ever felt rewarded for using Kubernetes, literally or metaphorically.

    • smitelli 5 days ago |
      Early on I heard the k8s controller ecosystem described as “a half dozen concurrent `while true` loops all fighting with each other.” Can’t say I disagree.
      • pphysch 5 days ago |
        Isn't that distributed systems in a nutshell?
        • nejsjsjsbsb 3 days ago |
          Node.js in a nutshell for sure
      • ithkuil 4 days ago |
        Isn't that what we all are?
    • Abhisman 4 days ago |
      Eh, dont you feel rewarded solving problems in general?
      • kevmo314 4 days ago |
        Can't say I feel like Kubernetes has solved more of my problems than it created.
        • melodyogonna 3 days ago |
          Are you doing datacenter-scale deployment and configuration?
          • kevmo314 3 days ago |
            Yup
            • melodyogonna 2 days ago |
              And you don't think Kubernetes solves a lot more problems than it creates? Very interesting, I wonder what you're comparing to.
  • dgfitz 5 days ago |
    I hope I've avoided containers enough to let this phase pass by. Formalizing vocabulary around the different states of a container makes me want to throw up my hands in a Seinfeld "come one" motion.
    • Leo_Verto 5 days ago |
      Like it or not, containers are here to stay. They just make way too much sense as an atomic unit for delivering applicstions and really aren't that complicated.

      Kubernetes is a whole nother beast though and while it introduces a ton of overhead, it can be useful at a certain organisational scale as an API definition for delivering services to other teams.

    • crabbone 4 days ago |
      This isn't about the state of container. It's about interactions between several containers (a group of containers is called a pod). Which, probably, doesn't make it better for you, but for the sake of correctness...