nixos/kubernetes: Stabilize services startup across machines
by adding targets and curl wait loops to services to ensure services are not started before their depended services are reachable. Extra targets cfssl-online.target and kube-apiserver-online.target syncronize starts across machines and node-online.target ensures docker is restarted and ready to deploy containers on after flannel has discussed the network cidr with apiserver. Since flannel needs to be started before addon-manager to configure the docker interface, it has to have its own rbac bootstrap service. The curl wait loops within the other services exists to ensure that when starting the service it is able to do its work immediately without clobbering the log about failing conditions. By ensuring kubernetes.target is only reached after starting the cluster it can be used in the tests as a wait condition. In kube-certmgr-bootstrap mkdir is needed for it to not fail to start. The following is the relevant part of systemctl list-dependencies default.target ● ├─certmgr.service ● ├─cfssl.service ● ├─docker.service ● ├─etcd.service ● ├─flannel.service ● ├─kubernetes.target ● │ ├─kube-addon-manager.service ● │ ├─kube-proxy.service ● │ ├─kube-apiserver-online.target ● │ │ ├─flannel-rbac-bootstrap.service ● │ │ ├─kube-apiserver-online.service ● │ │ ├─kube-apiserver.service ● │ │ ├─kube-controller-manager.service ● │ │ └─kube-scheduler.service ● │ └─node-online.target ● │ ├─node-online.service ● │ ├─flannel.target ● │ │ ├─flannel.service ● │ │ └─mk-docker-opts.service ● │ └─kubelet.target ● │ └─kubelet.service ● ├─network-online.target ● │ └─cfssl-online.target ● │ ├─certmgr.service ● │ ├─cfssl-online.service ● │ └─kube-certmgr-bootstrap.service
This commit is contained in:
parent
f9e2f76a59
commit
62f03750e4
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@ -72,7 +72,7 @@ in
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systemd.services.kube-addon-manager = {
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description = "Kubernetes addon manager";
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wantedBy = [ "kubernetes.target" ];
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after = [ "kube-apiserver.service" ];
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after = [ "kube-apiserver-online.target" "node-online.target" ];
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environment.ADDON_PATH = "/etc/kubernetes/addons/";
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path = [ pkgs.gawk ];
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serviceConfig = {
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@ -293,8 +293,9 @@ in
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in {
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systemd.services.kube-apiserver = {
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description = "Kubernetes APIServer Service";
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wantedBy = [ "kubernetes.target" ];
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after = [ "network.target" ];
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wantedBy = [ "kube-apiserver-online.target" ];
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after = [ "certmgr.service" ];
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before = [ "kube-apiserver-online.target" ];
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serviceConfig = {
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Slice = "kubernetes.slice";
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ExecStart = ''${top.package}/bin/kube-apiserver \
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@ -459,7 +460,28 @@ in
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};
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}))
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{
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systemd.targets.kube-apiserver-online = {
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wantedBy = [ "kubernetes.target" ];
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before = [ "kubernetes.target" ];
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};
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systemd.services.kube-apiserver-online = mkIf top.flannel.enable {
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description = "apiserver control plane is online";
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wantedBy = [ "kube-apiserver-online.target" ];
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after = [ "kube-scheduler.service" "kube-controller-manager.service" ];
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before = [ "kube-apiserver-online.target" ];
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preStart = ''
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${top.lib.mkWaitCurl (with top.pki.certs.flannelClient; {
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sleep = 3;
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path = "/healthz";
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cacert = top.caFile;
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inherit cert key;
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})}
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'';
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script = "echo apiserver control plane is online";
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};
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}
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];
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}
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@ -116,8 +116,17 @@ in
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systemd.services.kube-controller-manager = {
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description = "Kubernetes Controller Manager Service";
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wantedBy = [ "kubernetes.target" ];
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wantedBy = [ "kube-apiserver-online.target" ];
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after = [ "kube-apiserver.service" ];
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before = [ "kube-apiserver-online.target" ];
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preStart = ''
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${top.lib.mkWaitCurl (with top.pki.certs.controllerManagerClient; {
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sleep = 1;
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path = "/api";
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cacert = top.caFile;
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inherit cert key;
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})}
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'';
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serviceConfig = {
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RestartSec = "30s";
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Restart = "on-failure";
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@ -73,6 +73,18 @@ let
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};
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};
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mkWaitCurl = { address ? cfg.apiserverAddress, sleep ? 2, path ? "", args ? "-o /dev/null",
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cacert ? null, cert ? null, key ? null, }: ''
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while ! ${pkgs.curl}/bin/curl --fail-early -fs \
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${if cacert != null then "--cacert ${cacert}" else ""} \
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${if cert != null then "--cert ${cert}" else ""} \
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${if key != null then "--key ${key}" else ""} \
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${address}${path} ${args} ; do
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sleep ${toString sleep}
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echo Waiting to be able to reach ${address}${path}
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done
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'';
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kubeConfigDefaults = {
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server = mkDefault cfg.kubeconfig.server;
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caFile = mkDefault cfg.kubeconfig.caFile;
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@ -162,6 +174,7 @@ in {
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inherit mkCert;
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inherit mkKubeConfig;
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inherit mkKubeConfigOptions;
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inherit mkWaitCurl;
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};
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type = types.attrs;
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};
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@ -27,7 +27,12 @@ in
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};
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###### implementation
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config = mkIf cfg.enable {
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config = mkIf cfg.enable (let
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flannelBootstrapPaths = mkIf top.apiserver.enable [
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top.pki.certs.clusterAdmin.cert
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top.pki.certs.clusterAdmin.key
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];
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in {
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services.flannel = {
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enable = mkDefault true;
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@ -48,8 +53,10 @@ in
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}];
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};
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systemd.services."mk-docker-opts" = {
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systemd.services.mk-docker-opts = {
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description = "Pre-Docker Actions";
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wantedBy = [ "flannel.target" ];
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before = [ "flannel.target" ];
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path = with pkgs; [ gawk gnugrep ];
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script = ''
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${mkDockerOpts}/mk-docker-opts -d /run/flannel/docker
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@ -68,6 +75,17 @@ in
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};
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};
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systemd.targets.flannel = {
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wantedBy = [ "node-online.target" ];
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before = [ "node-online.target" ];
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};
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systemd.services.flannel = {
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wantedBy = [ "flannel.target" ];
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after = [ "kubelet.target" ];
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before = [ "flannel.target" ];
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};
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systemd.services.docker = {
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environment.DOCKER_OPTS = "-b none";
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serviceConfig.EnvironmentFile = "-/run/flannel/docker";
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@ -93,8 +111,14 @@ in
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};
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# give flannel som kubernetes rbac permissions if applicable
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services.kubernetes.addonManager.bootstrapAddons = mkIf ((storageBackend == "kubernetes") && (elem "RBAC" top.apiserver.authorizationMode)) {
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systemd.services.flannel-rbac-bootstrap = mkIf (top.apiserver.enable && (elem "RBAC" top.apiserver.authorizationMode)) {
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wantedBy = [ "kube-apiserver-online.target" ];
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after = [ "kube-apiserver-online.target" ];
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before = [ "flannel.service" ];
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path = with pkgs; [ kubectl ];
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preStart = let
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files = mapAttrsToList (n: v: pkgs.writeText "${n}.json" (builtins.toJSON v)) {
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flannel-cr = {
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apiVersion = "rbac.authorization.k8s.io/v1beta1";
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kind = "ClusterRole";
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@ -130,7 +154,26 @@ in
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name = "flannel-client";
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}];
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};
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};
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in ''
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${top.lib.mkWaitCurl (with top.pki.certs.clusterAdmin; {
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path = "/";
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cacert = top.caFile;
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inherit cert key;
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})}
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kubectl -s ${top.apiserverAddress} --certificate-authority=${top.caFile} --client-certificate=${top.pki.certs.clusterAdmin.cert} --client-key=${top.pki.certs.clusterAdmin.key} apply -f ${concatStringsSep " \\\n -f " files}
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'';
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script = "echo Ok";
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unitConfig.ConditionPathExists = flannelBootstrapPaths;
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};
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systemd.paths.flannel-rbac-bootstrap = mkIf top.apiserver.enable {
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wantedBy = [ "flannel-rbac-bootstrap.service" ];
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pathConfig = {
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PathExists = flannelBootstrapPaths;
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PathChanged = flannelBootstrapPaths;
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};
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};
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});
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}
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@ -252,8 +252,9 @@ in
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systemd.services.kubelet = {
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description = "Kubernetes Kubelet Service";
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wantedBy = [ "kubernetes.target" ];
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after = [ "network.target" "docker.service" "kube-apiserver.service" ];
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wantedBy = [ "kubelet.target" ];
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after = [ "kube-apiserver-online.target" ];
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before = [ "kubelet.target" ];
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path = with pkgs; [ gitMinimal openssh docker utillinux iproute ethtool thin-provisioning-tools iptables socat ] ++ top.path;
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preStart = ''
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${concatMapStrings (img: ''
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};
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};
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systemd.services.docker.before = [ "kubelet.service" ];
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systemd.services.node-online = {
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wantedBy = [ "node-online.target" ];
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after = [ "flannel.target" "kubelet.target" ];
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before = [ "node-online.target" ];
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# it is complicated. flannel needs kubelet to run the pause container before
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# it discusses the node CIDR with apiserver and afterwards configures and restarts
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# dockerd. Until then prevent creating any pods because they have to be recreated anyway
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# because the network of docker0 has been changed by flannel.
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script = let
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docker-env = "/run/flannel/docker";
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flannel-date = "stat --print=%Y ${docker-env}";
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docker-date = "systemctl show --property=ActiveEnterTimestamp --value docker";
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in ''
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while ! test -f ${docker-env} ; do sleep 1 ; done
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while test `${flannel-date}` -gt `date +%s --date="$(${docker-date})"` ; do
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sleep 1
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done
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'';
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serviceConfig.Type = "oneshot";
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serviceConfig.Slice = "kubernetes.slice";
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};
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# Allways include cni plugins
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services.kubernetes.kubelet.cni.packages = [pkgs.cni-plugins];
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};
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})
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{
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systemd.targets.kubelet = {
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wantedBy = [ "node-online.target" ];
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before = [ "node-online.target" ];
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};
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systemd.targets.node-online = {
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wantedBy = [ "kubernetes.target" ];
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before = [ "kubernetes.target" ];
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};
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}
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];
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}
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@ -119,6 +119,7 @@ in
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cfsslCertPathPrefix = "${config.services.cfssl.dataDir}/cfssl";
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cfsslCert = "${cfsslCertPathPrefix}.pem";
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cfsslKey = "${cfsslCertPathPrefix}-key.pem";
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cfsslPort = toString config.services.cfssl.port;
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certmgrPaths = [
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top.caFile
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chown cfssl "${cfsslAPITokenPath}" && chmod 400 "${cfsslAPITokenPath}"
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'')]);
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systemd.targets.cfssl-online = {
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wantedBy = [ "network-online.target" ];
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after = [ "cfssl.service" "network-online.target" "cfssl-online.service" ];
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};
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systemd.services.cfssl-online = {
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description = "Wait for ${remote} to be reachable.";
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wantedBy = [ "cfssl-online.target" ];
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before = [ "cfssl-online.target" ];
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preStart = ''
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${top.lib.mkWaitCurl {
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address = remote;
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path = "/api/v1/cfssl/info";
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args = "-kd '{}' -o /dev/null";
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}}
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'';
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script = "echo Ok";
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serviceConfig = {
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TimeoutSec = "300";
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};
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};
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systemd.services.kube-certmgr-bootstrap = {
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description = "Kubernetes certmgr bootstrapper";
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wantedBy = [ "certmgr.service" ];
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after = [ "cfssl.target" ];
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wantedBy = [ "cfssl-online.target" ];
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after = [ "cfssl-online.target" ];
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before = [ "certmgr.service" ];
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script = concatStringsSep "\n" [''
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set -e
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mkdir -p $(dirname ${certmgrAPITokenPath})
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mkdir -p $(dirname ${top.caFile})
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# If there's a cfssl (cert issuer) running locally, then don't rely on user to
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# manually paste it in place. Just symlink.
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# otherwise, create the target file, ready for users to insert the token
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fi
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''
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(optionalString (cfg.pkiTrustOnBootstrap) ''
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if [ ! -f "${top.caFile}" ] || [ $(cat "${top.caFile}" | wc -c) -lt 1 ]; then
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${pkgs.curl}/bin/curl --fail-early -f -kd '{}' ${remote}/api/v1/cfssl/info | \
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${pkgs.cfssl}/bin/cfssljson -stdout >${top.caFile}
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if [ ! -s "${top.caFile}" ]; then
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${top.lib.mkWaitCurl {
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address = "https://${top.masterAddress}:${cfsslPort}";
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path = "/api/v1/cfssl/info";
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args = "-kd '{}' -o - | ${pkgs.cfssl}/bin/cfssljson -stdout >${top.caFile}";
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}}
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fi
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'')
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];
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serviceConfig = {
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RestartSec = "10s";
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TimeoutSec = "300";
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RestartSec = "1s";
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Restart = "on-failure";
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};
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};
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@ -254,6 +285,14 @@ in
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};
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systemd.services.certmgr = {
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wantedBy = [ "cfssl-online.target" ];
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after = [ "cfssl-online.target" "kube-certmgr-bootstrap.service" ];
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preStart = ''
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while ! test -s ${certmgrAPITokenPath} ; do
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sleep 1
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echo Waiting for ${certmgrAPITokenPath}
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done
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'';
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unitConfig.ConditionPathExists = certmgrPaths;
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};
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@ -289,6 +328,12 @@ in
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''
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export KUBECONFIG=${clusterAdminKubeconfig}
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${kubectl}/bin/kubectl apply -f ${concatStringsSep " \\\n -f " files}
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${top.lib.mkWaitCurl (with top.pki.certs.addonManager; {
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path = "/api/v1/namespaces/kube-system/serviceaccounts/default";
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cacert = top.caFile;
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inherit cert key;
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})}
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'';
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})
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{
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};
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systemd.services.flannel = {
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preStart = ''
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${top.lib.mkWaitCurl (with top.pki.certs.flannelClient; {
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path = "/api/v1/nodes";
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cacert = top.caFile;
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inherit cert key;
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args = "-o - | grep podCIDR >/dev/null";
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})}
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'';
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unitConfig.ConditionPathExists = flannelPaths;
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};
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@ -49,8 +49,16 @@ in
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systemd.services.kube-proxy = {
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description = "Kubernetes Proxy Service";
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wantedBy = [ "kubernetes.target" ];
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after = [ "kube-apiserver.service" ];
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after = [ "node-online.target" ];
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before = [ "kubernetes.target" ];
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path = with pkgs; [ iptables conntrack_tools ];
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preStart = ''
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${top.lib.mkWaitCurl (with top.pki.certs.kubeProxyClient; {
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path = "/api/v1/nodes/${top.kubelet.hostname}";
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cacert = top.caFile;
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inherit cert key;
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})}
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'';
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serviceConfig = {
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Slice = "kubernetes.slice";
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ExecStart = ''${top.package}/bin/kube-proxy \
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|
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@ -59,8 +59,17 @@ in
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config = mkIf cfg.enable {
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systemd.services.kube-scheduler = {
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description = "Kubernetes Scheduler Service";
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wantedBy = [ "kubernetes.target" ];
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wantedBy = [ "kube-apiserver-online.target" ];
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after = [ "kube-apiserver.service" ];
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before = [ "kube-apiserver-online.target" ];
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preStart = ''
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${top.lib.mkWaitCurl (with top.pki.certs.schedulerClient; {
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sleep = 1;
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path = "/api";
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cacert = top.caFile;
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inherit cert key;
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})}
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'';
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serviceConfig = {
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Slice = "kubernetes.slice";
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ExecStart = ''${top.package}/bin/kube-scheduler \
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@ -77,6 +77,7 @@ let
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singleNodeTest = {
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test = ''
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# prepare machine1 for test
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$machine1->waitForUnit("kubernetes.target");
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$machine1->waitUntilSucceeds("kubectl get node machine1.${domain} | grep -w Ready");
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$machine1->waitUntilSucceeds("docker load < ${redisImage}");
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$machine1->waitUntilSucceeds("kubectl create -f ${redisPod}");
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@ -102,6 +103,8 @@ let
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# Node token exchange
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$machine1->waitUntilSucceeds("cp -f /var/lib/cfssl/apitoken.secret /tmp/shared/apitoken.secret");
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$machine2->waitUntilSucceeds("cat /tmp/shared/apitoken.secret | nixos-kubernetes-node-join");
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$machine1->waitForUnit("kubernetes.target");
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$machine2->waitForUnit("kubernetes.target");
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# prepare machines for test
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$machine1->waitUntilSucceeds("kubectl get node machine2.${domain} | grep -w Ready");
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|
|
@ -94,6 +94,8 @@ let
|
|||
|
||||
singlenode = base // {
|
||||
test = ''
|
||||
$machine1->waitForUnit("kubernetes.target");
|
||||
|
||||
$machine1->waitUntilSucceeds("kubectl get node machine1.my.zyx | grep -w Ready");
|
||||
|
||||
$machine1->waitUntilSucceeds("docker load < ${kubectlImage}");
|
||||
|
@ -116,6 +118,8 @@ let
|
|||
# Node token exchange
|
||||
$machine1->waitUntilSucceeds("cp -f /var/lib/cfssl/apitoken.secret /tmp/shared/apitoken.secret");
|
||||
$machine2->waitUntilSucceeds("cat /tmp/shared/apitoken.secret | nixos-kubernetes-node-join");
|
||||
$machine1->waitForUnit("kubernetes.target");
|
||||
$machine2->waitForUnit("kubernetes.target");
|
||||
|
||||
$machine1->waitUntilSucceeds("kubectl get node machine2.my.zyx | grep -w Ready");
|
||||
|
||||
|
|
Loading…
Reference in a new issue