graph.gv

digraph {
    node[shape=rect, color=cornflowerblue, style="bold"];
    graph[pad="0", nodesep="0.2", ranksep="0"];
    edge[color="darkgreen"];

    /********** NODES **********/
    // Outer objects
    subgraph cluster_no_resources {
        label="Not K8S resources";
        color="grey";

        container[label="Container",   URL="https://www.docker.com/resources/what-container"];
        image[label="Image",           URL="https://kubernetes.io/docs/concepts/containers/images/"];
    }

    // Base
    subgraph cluster_workload {
        label="Workload";
        color="grey";

        pod[label="Pod", URL="https://kubernetes.io/docs/concepts/workloads/pods/pod/"];
    }

    // Controllers
    subgraph cluster_controllers {
        label="Controllers";
        color="grey";

        deployment[label="Deployment", URL="https://kubernetes.io/docs/concepts/workloads/controllers/deployment/"];
        replicaset[label="ReplicaSet", URL="https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/"];
        // replication_controller[label="ReplicationController", URL="https://kubernetes.io/docs/concepts/workloads/controllers/replicationcontroller/"];
        statefulset[label="StatefulSet", URL="https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/"];
        daemonset[label="DaemonSet",     URL="https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/"];

        {rank=same;
            replicaset;
            statefulset;
            daemonset
            };

    }

    // Jobs
    subgraph cluster_jobs {
        label="Jobs";
        color="grey";

        job[label="Job",         URL="https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/"];
        cronjob[label="CronJob", URL="https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/"];
    }

    // Services, load balancing & networking
    subgraph cluster_services {
        label="Services, load balancing & networking";
        color="grey";

        // endpoint_slice[label="EndpointSlice", style="dashed", URL="https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/"];
        service[label="Service",                              URL="https://kubernetes.io/docs/concepts/services-networking/service/"];
        ingress[label="Ingress",                              URL="https://kubernetes.io/docs/concepts/services-networking/ingress/"];
        ingress_controller[label="Ingress Controller",        URL="https://kubernetes.io/docs/concepts/services-networking/ingress-controllers/"];
        // network_policy[label="Network Policy",                URL="https://kubernetes.io/docs/concepts/services-networking/network-policies/"];
    }

    // Storage
    subgraph cluster_storage {
        label="Storage";
        color="grey";

        volume[label="Volume",                                   URL="https://kubernetes.io/docs/concepts/storage/volumes/"];
        persistent_volume[label="Persistent Volume",             URL="https://kubernetes.io/docs/concepts/storage/persistent-volumes/"];
        persistent_volume_claim[label="PersistentVolumeClaim",   URL="https://kubernetes.io/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims"];
        volume_snapshot[label="Volume Snapshot",                 URL="https://kubernetes.io/docs/concepts/storage/volume-snapshots/"];
        volume_snapshot_content[label="Volume Snapshot Content", URL="https://kubernetes.io/docs/concepts/storage/volume-snapshots/"];
        storage_class[label="Storage Class",                     URL="https://kubernetes.io/docs/concepts/storage/storage-classes/"];
        volume_snapshot_class[label="Volume Snapshot Class",     URL="https://kubernetes.io/docs/concepts/storage/volume-snapshot-classes/"];
        configmap[label="ConfigMap",                             URL="https://kubernetes.io/docs/concepts/storage/volumes/#configmap"];

        {rank=same;
            persistent_volume;
            persistent_volume_claim;
            volume_snapshot_content;
        }
    }

    // Configuration
    subgraph cluster_configuration {
        label="Configuration";
        color="grey";

        secret[label="Secret", URL="https://kubernetes.io/docs/concepts/configuration/secret/"];
    }

    // Permissions
    subgraph cluster_permissions {
        label="Permissions";
        color="grey";
        rankdir=LR;

        // Namespace specific
        subgraph cluster_namespace_permissions {
            label="Namespace-specific";

            rolebinding[label="Role Binding",        URL="https://kubernetes.io/docs/reference/access-authn-authz/rbac/#rolebinding-and-clusterrolebinding"];
            role[label="Role",                       URL="https://kubernetes.io/docs/reference/access-authn-authz/rbac/#role-and-clusterrole"];
            service_account[label="Service Account", URL="https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/"];

            {rank=same;
                rolebinding;
                role;}
        }

        // Cluster-wide
        subgraph cluster_global_permissions {
            label="Global";

            cluster_rolebinding[label="Cluster Role Binding",        URL="https://kubernetes.io/docs/reference/access-authn-authz/rbac/#rolebinding-and-clusterrolebinding"];
            cluster_role[label="Cluster Role",                       URL="https://kubernetes.io/docs/reference/access-authn-authz/rbac/#role-and-clusterrole"];
            cluster_service_account[label="Cluster Service Account", URL="https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/"];

            {rank=same;
                cluster_rolebinding;
                cluster_role;}
        }

    }

    /********** LINKS **********/
    // Controllers
    container -> image[label="Initialized with"];
    pod -> container[color=brown, label="Hosts several, sharing filesystem & network"];
    deployment -> replicaset[label="Deploys version as"];
    replicaset -> pod[color=darkslateblue,  label="Handles restart & replication of"];
    statefulset -> pod[color=darkslateblue, label="Deploys with \"sticky\" identity"];
    daemonset -> pod[color=darkslateblue,   label="Deploys one per node"];

    // replication_controller -> deployment[label="Recommended to replace with", style="dotted"];

    // Jobs
    cronjob -> job[label="Launches on a schedule"];
    job -> pod[color=darkslateblue, label="Is run as a"];

    // Services, load balancing & networking
    ingress_controller -> pod[color=darkslateblue, label="Run in a"];
    ingress_controller -> ingress[label="Routes based on"];

    ingress -> service[label="Routes external requests to"];
    service -> pod[color=darkslateblue, label="Routes (based on labels) to"];

    // Storage
    pod -> volume[color=brown, label="Stores data on"];
    pod -> secret[color=brown,            label="Initializes sensitive variables from"];
    pod -> secret[color=brown,            label="Stores sensitive data on"];
    pod -> configmap[color=brown,         label="Keeps configuration data on"];

    volume -> persistent_volume[label="Implemented as"];
    volume -> persistent_volume_claim[label="Implemented as"];

    persistent_volume_claim -> persistent_volume[label="A request for a"];
    persistent_volume -> storage_class[label="Provisioned with"];

    volume_snapshot -> volume_snapshot_content[label="Request the generation of a"];
    volume_snapshot_content -> volume_snapshot_class[label="Provisioned with"];
    volume_snapshot_content -> volume[style=dashed, label="Backups content of"];

    // Permissions
    rolebinding -> role[label="Grants permissions in ..."];
    rolebinding -> service_account[label="... to a"];
    cluster_rolebinding -> cluster_role[label="Grants permissions in ..."];
    cluster_rolebinding -> cluster_service_account[label="... to a"];

    service_account -> pod[color=darkslateblue, label="Provides identity to process running in a"];
    cluster_service_account -> pod[color=darkslateblue, label="Provides identity to process running in a"];
}