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Configuration
1 - Ceph Storage cluster with Rook
Preparation
Talos Linux reserves an entire disk for the OS installation, so machines with multiple available disks are needed for a reliable Ceph cluster with Rook and Talos Linux.
Rook requires that the block devices or partitions used by Ceph have no partitions or formatted filesystems before use.
Rook also requires a minimum Kubernetes version of v1.16 and Helm v3.0 for installation of charts.
It is highly recommended that the Rook Ceph overview is read and understood before deploying a Ceph cluster with Rook.
Installation
Creating a Ceph cluster with Rook requires two steps; first the Rook Operator needs to be installed which can be done with a Helm Chart.
The example below installs the Rook Operator into the rook-ceph namespace, which is the default for a Ceph cluster with Rook.
$ helm repo add rook-release https://charts.rook.io/release
"rook-release" has been added to your repositories
$ helm install --create-namespace --namespace rook-ceph rook-ceph rook-release/rook-ceph
W0327 17:52:44.277830 54987 warnings.go:70] policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
W0327 17:52:44.612243 54987 warnings.go:70] policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
NAME: rook-ceph
LAST DEPLOYED: Sun Mar 27 17:52:42 2022
NAMESPACE: rook-ceph
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The Rook Operator has been installed. Check its status by running:
kubectl --namespace rook-ceph get pods -l "app=rook-ceph-operator"
Visit https://rook.io/docs/rook/latest for instructions on how to create and configure Rook clusters
Important Notes:
- You must customize the 'CephCluster' resource in the sample manifests for your cluster.
- Each CephCluster must be deployed to its own namespace, the samples use `rook-ceph` for the namespace.
- The sample manifests assume you also installed the rook-ceph operator in the `rook-ceph` namespace.
- The helm chart includes all the RBAC required to create a CephCluster CRD in the same namespace.
- Any disk devices you add to the cluster in the 'CephCluster' must be empty (no filesystem and no partitions).
Once that is complete, the Ceph cluster can be installed with the official Helm Chart. The Chart can be installed with default values, which will attempt to use all nodes in the Kubernetes cluster, and all unused disks on each node for Ceph storage, and make available block storage, object storage, as well as a shared filesystem. Generally more specific node/device/cluster configuration is used, and the Rook documentation explains all the available options in detail. For this example the defaults will be adequate.
$ helm install --create-namespace --namespace rook-ceph rook-ceph-cluster --set operatorNamespace=rook-ceph rook-release/rook-ceph-cluster
NAME: rook-ceph-cluster
LAST DEPLOYED: Sun Mar 27 18:12:46 2022
NAMESPACE: rook-ceph
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The Ceph Cluster has been installed. Check its status by running:
kubectl --namespace rook-ceph get cephcluster
Visit https://rook.github.io/docs/rook/latest/ceph-cluster-crd.html for more information about the Ceph CRD.
Important Notes:
- You can only deploy a single cluster per namespace
- If you wish to delete this cluster and start fresh, you will also have to wipe the OSD disks using `sfdisk`
Now the Ceph cluster configuration has been created, the Rook operator needs time to install the Ceph cluster and bring all the components online. The progression of the Ceph cluster state can be followed with the following command.
$ watch kubectl --namespace rook-ceph get cephcluster rook-ceph
Every 2.0s: kubectl --namespace rook-ceph get cephcluster rook-ceph
NAME DATADIRHOSTPATH MONCOUNT AGE PHASE MESSAGE HEALTH EXTERNAL
rook-ceph /var/lib/rook 3 57s Progressing Configuring Ceph Mons
Depending on the size of the Ceph cluster and the availability of resources the Ceph cluster should become available, and with it the storage classes that can be used with Kubernetes Physical Volumes.
$ kubectl --namespace rook-ceph get cephcluster rook-ceph
NAME DATADIRHOSTPATH MONCOUNT AGE PHASE MESSAGE HEALTH EXTERNAL
rook-ceph /var/lib/rook 3 40m Ready Cluster created successfully HEALTH_OK
$ kubectl get storageclass
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
ceph-block (default) rook-ceph.rbd.csi.ceph.com Delete Immediate true 77m
ceph-bucket rook-ceph.ceph.rook.io/bucket Delete Immediate false 77m
ceph-filesystem rook-ceph.cephfs.csi.ceph.com Delete Immediate true 77m
Talos Linux Considerations
It is important to note that a Rook Ceph cluster saves cluster information directly onto the node (by default dataDirHostPath is set to /var/lib/rook).
If running only a single mon instance, cluster management is little bit more involved, as any time a Talos Linux node is reconfigured or upgraded, the partition that stores the /var file system is wiped, but the --preserve option of talosctl upgrade will ensure that doesn’t happen.
By default, Rook configues Ceph to have 3 mon instances, in which case the data stored in dataDirHostPath can be regenerated from the other mon instances.
So when performing maintenance on a Talos Linux node with a Rook Ceph cluster (e.g. upgrading the Talos Linux version), it is imperative that care be taken to maintain the health of the Ceph cluster.
Before upgrading, you should always check the health status of the Ceph cluster to ensure that it is healthy.
$ kubectl --namespace rook-ceph get cephclusters.ceph.rook.io rook-ceph
NAME DATADIRHOSTPATH MONCOUNT AGE PHASE MESSAGE HEALTH EXTERNAL
rook-ceph /var/lib/rook 3 98m Ready Cluster created successfully HEALTH_OK
If it is, you can begin the upgrade process for the Talos Linux node, during which time the Ceph cluster will become unhealthy as the node is reconfigured. Before performing any other action on the Talos Linux nodes, the Ceph cluster must return to a healthy status.
$ talosctl upgrade --nodes 172.20.15.5 --image ghcr.io/talos-systems/installer:v0.14.3
NODE ACK STARTED
172.20.15.5 Upgrade request received 2022-03-27 20:29:55.292432887 +0200 CEST m=+10.050399758
$ kubectl --namespace rook-ceph get cephclusters.ceph.rook.io
NAME DATADIRHOSTPATH MONCOUNT AGE PHASE MESSAGE HEALTH EXTERNAL
rook-ceph /var/lib/rook 3 99m Progressing Configuring Ceph Mgr(s) HEALTH_WARN
$ kubectl --namespace rook-ceph wait --timeout=1800s --for=jsonpath='{.status.ceph.health}=HEALTH_OK' rook-ceph
cephcluster.ceph.rook.io/rook-ceph condition met
The above steps need to be performed for each Talos Linux node undergoing maintenance, one at a time.
Cleaning Up
Rook Ceph Cluster Removal
Removing a Rook Ceph cluster requires a few steps, starting with signalling to Rook that the Ceph cluster is really being destroyed. Then all Persistent Volumes (and Claims) backed by the Ceph cluster must be deleted, followed by the Storage Classes and the Ceph storage types.
$ kubectl --namespace rook-ceph patch cephcluster rook-ceph --type merge -p '{"spec":{"cleanupPolicy":{"confirmation":"yes-really-destroy-data"}}}'
cephcluster.ceph.rook.io/rook-ceph patched
$ kubectl delete storageclasses ceph-block ceph-bucket ceph-filesystem
storageclass.storage.k8s.io "ceph-block" deleted
storageclass.storage.k8s.io "ceph-bucket" deleted
storageclass.storage.k8s.io "ceph-filesystem" deleted
$ kubectl --namespace rook-ceph delete cephblockpools ceph-blockpool
cephblockpool.ceph.rook.io "ceph-blockpool" deleted
$ kubectl --namespace rook-ceph delete cephobjectstore ceph-objectstore
cephobjectstore.ceph.rook.io "ceph-objectstore" deleted
$ kubectl --namespace rook-ceph delete cephfilesystem ceph-filesystem
cephfilesystem.ceph.rook.io "ceph-filesystem" deleted
Once that is complete, the Ceph cluster itself can be removed, along with the Rook Ceph cluster Helm chart installation.
$ kubectl --namespace rook-ceph delete cephcluster rook-ceph
cephcluster.ceph.rook.io "rook-ceph" deleted
$ helm --namespace rook-ceph uninstall rook-ceph-cluster
release "rook-ceph-cluster" uninstalled
If needed, the Rook Operator can also be removed along with all the Custom Resource Definitions that it created.
$ helm --namespace rook-ceph uninstall rook-ceph
W0328 12:41:14.998307 147203 warnings.go:70] policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
These resources were kept due to the resource policy:
[CustomResourceDefinition] cephblockpools.ceph.rook.io
[CustomResourceDefinition] cephbucketnotifications.ceph.rook.io
[CustomResourceDefinition] cephbuckettopics.ceph.rook.io
[CustomResourceDefinition] cephclients.ceph.rook.io
[CustomResourceDefinition] cephclusters.ceph.rook.io
[CustomResourceDefinition] cephfilesystemmirrors.ceph.rook.io
[CustomResourceDefinition] cephfilesystems.ceph.rook.io
[CustomResourceDefinition] cephfilesystemsubvolumegroups.ceph.rook.io
[CustomResourceDefinition] cephnfses.ceph.rook.io
[CustomResourceDefinition] cephobjectrealms.ceph.rook.io
[CustomResourceDefinition] cephobjectstores.ceph.rook.io
[CustomResourceDefinition] cephobjectstoreusers.ceph.rook.io
[CustomResourceDefinition] cephobjectzonegroups.ceph.rook.io
[CustomResourceDefinition] cephobjectzones.ceph.rook.io
[CustomResourceDefinition] cephrbdmirrors.ceph.rook.io
[CustomResourceDefinition] objectbucketclaims.objectbucket.io
[CustomResourceDefinition] objectbuckets.objectbucket.io
release "rook-ceph" uninstalled
$ kubectl delete crds cephblockpools.ceph.rook.io cephbucketnotifications.ceph.rook.io cephbuckettopics.ceph.rook.io \
cephclients.ceph.rook.io cephclusters.ceph.rook.io cephfilesystemmirrors.ceph.rook.io \
cephfilesystems.ceph.rook.io cephfilesystemsubvolumegroups.ceph.rook.io \
cephnfses.ceph.rook.io cephobjectrealms.ceph.rook.io cephobjectstores.ceph.rook.io \
cephobjectstoreusers.ceph.rook.io cephobjectzonegroups.ceph.rook.io cephobjectzones.ceph.rook.io \
cephrbdmirrors.ceph.rook.io objectbucketclaims.objectbucket.io objectbuckets.objectbucket.io
customresourcedefinition.apiextensions.k8s.io "cephblockpools.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephbucketnotifications.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephbuckettopics.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephclients.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephclusters.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephfilesystemmirrors.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephfilesystems.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephfilesystemsubvolumegroups.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephnfses.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephobjectrealms.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephobjectstores.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephobjectstoreusers.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephobjectzonegroups.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephobjectzones.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "cephrbdmirrors.ceph.rook.io" deleted
customresourcedefinition.apiextensions.k8s.io "objectbucketclaims.objectbucket.io" deleted
customresourcedefinition.apiextensions.k8s.io "objectbuckets.objectbucket.io" deleted
Talos Linux Rook Metadata Removal
If the Rook Operator is cleanly removed following the above process, the node metadata and disks should be clean and ready to be re-used.
In the case of an unclean cluster removal, there may be still a few instances of metadata stored on the system disk, as well as the partition information on the storage disks.
First the node metadata needs to be removed, make sure to update the nodeName with the actual name of a storage node that needs cleaning, and path with the Rook configuration dataDirHostPath set when installing the chart.
The following will need to be repeated for each node used in the Rook Ceph cluster.
$ cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: disk-clean
spec:
restartPolicy: Never
nodeName: <storage-node-name>
volumes:
- name: rook-data-dir
hostPath:
path: <dataDirHostPath>
containers:
- name: disk-clean
image: busybox
securityContext:
privileged: true
volumeMounts:
- name: rook-data-dir
mountPath: /node/rook-data
command: ["/bin/sh", "-c", "rm -rf /node/rook-data/*"]
EOF
pod/disk-clean created
$ kubectl wait --timeout=900s --for=jsonpath='{.status.phase}=Succeeded' pod disk-clean
pod/disk-clean condition met
$ kubectl delete pod disk-clean
pod "disk-clean" deleted
Lastly, the disks themselves need the partition and filesystem data wiped before they can be reused.
Again, the following as to be repeated for each node and disk used in the Rook Ceph cluster, updating nodeName and of= in the command as needed.
$ cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: disk-wipe
spec:
restartPolicy: Never
nodeName: <storage-node-name>
containers:
- name: disk-wipe
image: busybox
securityContext:
privileged: true
command: ["/bin/sh", "-c", "dd if=/dev/zero bs=1M count=100 oflag=direct of=<device>"]
EOF
pod/disk-wipe created
$ kubectl wait --timeout=900s --for=jsonpath='{.status.phase}=Succeeded' pod disk-wipe
pod/disk-wipe condition met
$ kubectl delete pod disk-clean
pod "disk-wipe" deleted
2 - Cluster Endpoint
In this section, we will step through the configuration of a Talos based Kubernetes cluster. There are three major components we will configure:
apidandtalosctl- the master nodes
- the worker nodes
Talos enforces a high level of security by using mutual TLS for authentication and authorization.
We recommend that the configuration of Talos be performed by a cluster owner. A cluster owner should be a person of authority within an organization, perhaps a director, manager, or senior member of a team. They are responsible for storing the root CA, and distributing the PKI for authorized cluster administrators.
Recommended settings
Talos runs great out of the box, but if you tweak some minor settings it will make your life a lot easier in the future. This is not a requirement, but rather a document to explain some key settings.
Endpoint
To configure the talosctl endpoint, it is recommended you use a resolvable DNS name.
This way, if you decide to upgrade to a multi-controlplane cluster you only have to add the ip address to the hostname configuration.
The configuration can either be done on a Loadbalancer, or simply trough DNS.
For example:
This is in the config file for the cluster e.g. controlplane.yaml and worker.yaml. for more details, please see: v1alpha1 endpoint configuration
.....
cluster:
controlPlane:
endpoint: https://endpoint.example.local:6443
.....
If you have a DNS name as the endpoint, you can upgrade your talos cluster with multiple controlplanes in the future (if you don’t have a multi-controlplane setup from the start) Using a DNS name generates the corresponding Certificates (Kubernetes and Talos) for the correct hostname.
3 - Deploying Metrics Server
Metrics Server enables use of the Horizontal Pod Autoscaler and Vertical Pod Autoscaler. It does this by gathering metrics data from the kubelets in a cluster. By default, the certificates in use by the kubelets will not be recognized by metrics-server. This can be solved by either configuring metrics-server to do no validation of the TLS certificates, or by modifying the kubelet configuration to rotate its certificates and use ones that will be recognized by metrics-server.
Node Configuration
To enable kubelet certificate rotation, all nodes should have the following Machine Config snippet:
machine:
kubelet:
extraArgs:
rotate-server-certificates: true
Install During Bootstrap
We will want to ensure that new certificates for the kubelets are approved automatically. This can easily be done with the Kubelet Serving Certificate Approver, which will automatically approve the Certificate Signing Requests generated by the kubelets.
We can have Kubelet Serving Certificate Approver and metrics-server installed on the cluster automatically during bootstrap by adding the following snippet to the Cluster Config of the node that will be handling the bootstrap process:
cluster:
extraManifests:
- https://raw.githubusercontent.com/alex1989hu/kubelet-serving-cert-approver/main/deploy/standalone-install.yaml
- https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
Install After Bootstrap
If you choose not to use extraManifests to install Kubelet Serving Certificate Approver and metrics-server during bootstrap, you can install them once the cluster is online using kubectl:
kubectl apply -f https://raw.githubusercontent.com/alex1989hu/kubelet-serving-cert-approver/main/deploy/standalone-install.yaml
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
4 - Discovery
Video Walkthrough
To see a live demo of Cluster Discovery, see the video below:
Registries
Peers are aggregated from a number of optional registries.
By default, Talos will use the kubernetes and service registries.
Either one can be disabled.
To disable a registry, set disabled to true (this option is the same for all registries):
For example, to disable the service registry:
cluster:
discovery:
enabled: true
registries:
service:
disabled: true
Disabling all registries effectively disables member discovery altogether.
Talos supports the
kubernetesandserviceregistries.
Kubernetes registry uses Kubernetes Node resource data and additional Talos annotations:
$ kubectl describe node <nodename>
Annotations: cluster.talos.dev/node-id: Utoh3O0ZneV0kT2IUBrh7TgdouRcUW2yzaaMl4VXnCd
networking.talos.dev/assigned-prefixes: 10.244.0.0/32,10.244.0.1/24
networking.talos.dev/self-ips: 172.20.0.2,fd83:b1f7:fcb5:2802:8c13:71ff:feaf:7c94
...
Service registry uses external Discovery Service to exchange encrypted information about cluster members.
Resource Definitions
Talos provides seven resources that can be used to introspect the new discovery and KubeSpan features.
Discovery
Identities
The node’s unique identity (base62 encoded random 32 bytes) can be obtained with:
Note: Using base62 allows the ID to be URL encoded without having to use the ambiguous URL-encoding version of base64.
$ talosctl get identities -o yaml
...
spec:
nodeId: Utoh3O0ZneV0kT2IUBrh7TgdouRcUW2yzaaMl4VXnCd
Node identity is used as the unique Affiliate identifier.
Node identity resource is preserved in the STATE partition in node-identity.yaml file.
Node identity is preserved across reboots and upgrades, but it is regenerated if the node is reset (wiped).
Affiliates
An affiliate is a proposed member attributed to the fact that the node has the same cluster ID and secret.
$ talosctl get affiliates
ID VERSION HOSTNAME MACHINE TYPE ADDRESSES
2VfX3nu67ZtZPl57IdJrU87BMjVWkSBJiL9ulP9TCnF 2 talos-default-master-2 controlplane ["172.20.0.3","fd83:b1f7:fcb5:2802:986b:7eff:fec5:889d"]
6EVq8RHIne03LeZiJ60WsJcoQOtttw1ejvTS6SOBzhUA 2 talos-default-worker-1 worker ["172.20.0.5","fd83:b1f7:fcb5:2802:cc80:3dff:fece:d89d"]
NVtfu1bT1QjhNq5xJFUZl8f8I8LOCnnpGrZfPpdN9WlB 2 talos-default-worker-2 worker ["172.20.0.6","fd83:b1f7:fcb5:2802:2805:fbff:fe80:5ed2"]
Utoh3O0ZneV0kT2IUBrh7TgdouRcUW2yzaaMl4VXnCd 4 talos-default-master-1 controlplane ["172.20.0.2","fd83:b1f7:fcb5:2802:8c13:71ff:feaf:7c94"]
b3DebkPaCRLTLLWaeRF1ejGaR0lK3m79jRJcPn0mfA6C 2 talos-default-master-3 controlplane ["172.20.0.4","fd83:b1f7:fcb5:2802:248f:1fff:fe5c:c3f"]
One of the Affiliates with the ID matching node identity is populated from the node data, other Affiliates are pulled from the registries.
Enabled discovery registries run in parallel and discovered data is merged to build the list presented above.
Details about data coming from each registry can be queried from the cluster-raw namespace:
$ talosctl get affiliates --namespace=cluster-raw
ID VERSION HOSTNAME MACHINE TYPE ADDRESSES
k8s/2VfX3nu67ZtZPl57IdJrU87BMjVWkSBJiL9ulP9TCnF 3 talos-default-master-2 controlplane ["172.20.0.3","fd83:b1f7:fcb5:2802:986b:7eff:fec5:889d"]
k8s/6EVq8RHIne03LeZiJ60WsJcoQOtttw1ejvTS6SOBzhUA 2 talos-default-worker-1 worker ["172.20.0.5","fd83:b1f7:fcb5:2802:cc80:3dff:fece:d89d"]
k8s/NVtfu1bT1QjhNq5xJFUZl8f8I8LOCnnpGrZfPpdN9WlB 2 talos-default-worker-2 worker ["172.20.0.6","fd83:b1f7:fcb5:2802:2805:fbff:fe80:5ed2"]
k8s/b3DebkPaCRLTLLWaeRF1ejGaR0lK3m79jRJcPn0mfA6C 3 talos-default-master-3 controlplane ["172.20.0.4","fd83:b1f7:fcb5:2802:248f:1fff:fe5c:c3f"]
service/2VfX3nu67ZtZPl57IdJrU87BMjVWkSBJiL9ulP9TCnF 23 talos-default-master-2 controlplane ["172.20.0.3","fd83:b1f7:fcb5:2802:986b:7eff:fec5:889d"]
service/6EVq8RHIne03LeZiJ60WsJcoQOtttw1ejvTS6SOBzhUA 26 talos-default-worker-1 worker ["172.20.0.5","fd83:b1f7:fcb5:2802:cc80:3dff:fece:d89d"]
service/NVtfu1bT1QjhNq5xJFUZl8f8I8LOCnnpGrZfPpdN9WlB 20 talos-default-worker-2 worker ["172.20.0.6","fd83:b1f7:fcb5:2802:2805:fbff:fe80:5ed2"]
service/b3DebkPaCRLTLLWaeRF1ejGaR0lK3m79jRJcPn0mfA6C 14 talos-default-master-3 controlplane ["172.20.0.4","fd83:b1f7:fcb5:2802:248f:1fff:fe5c:c3f"]
Each Affiliate ID is prefixed with k8s/ for data coming from the Kubernetes registry and with service/ for data coming from the discovery service.
Members
A member is an affiliate that has been approved to join the cluster. The members of the cluster can be obtained with:
$ talosctl get members
ID VERSION HOSTNAME MACHINE TYPE OS ADDRESSES
talos-default-master-1 2 talos-default-master-1 controlplane Talos (v1.0.6) ["172.20.0.2","fd83:b1f7:fcb5:2802:8c13:71ff:feaf:7c94"]
talos-default-master-2 1 talos-default-master-2 controlplane Talos (v1.0.6) ["172.20.0.3","fd83:b1f7:fcb5:2802:986b:7eff:fec5:889d"]
talos-default-master-3 1 talos-default-master-3 controlplane Talos (v1.0.6) ["172.20.0.4","fd83:b1f7:fcb5:2802:248f:1fff:fe5c:c3f"]
talos-default-worker-1 1 talos-default-worker-1 worker Talos (v1.0.6) ["172.20.0.5","fd83:b1f7:fcb5:2802:cc80:3dff:fece:d89d"]
talos-default-worker-2 1 talos-default-worker-2 worker Talos (v1.0.6) ["172.20.0.6","fd83:b1f7:fcb5:2802:2805:fbff:fe80:5ed2"]
5 - Pod Security
Kubernetes deprecated Pod Security Policy as of v1.21, and it is going to be removed in v1.25. Pod Security Policy was replaced with Pod Security Admission. Pod Security Admission is alpha in v1.22 (requires a feature gate) and beta in v1.23 (enabled by default).
In this guide we are going to enable and configure Pod Security Admission in Talos.
Configuration
Prepare the following machine configuration patch and store it in the pod-security-patch.yaml:
- op: add
path: /cluster/apiServer/admissionControl
value:
- name: PodSecurity
configuration:
apiVersion: pod-security.admission.config.k8s.io/v1alpha1
kind: PodSecurityConfiguration
defaults:
enforce: "baseline"
enforce-version: "latest"
audit: "restricted"
audit-version: "latest"
warn: "restricted"
warn-version: "latest"
exemptions:
usernames: []
runtimeClasses: []
namespaces: [kube-system]
This is a cluster-wide configuration for the Pod Security Admission plugin:
- by default
baselinePod Security Standard profile is enforced - more strict
restrictedprofile is not enforced, but API server warns about found issues
Generate Talos machine configuration applying the patch above:
talosctl gen config cluster1 https://<IP>:6443/ --config-patch-control-plane @../pod-security-patch.yaml
Deploy Talos using the generated machine configuration.
Verify current admission plugin configuration with:
$ talosctl get kubernetescontrolplaneconfigs apiserver-admission-control -o yaml
node: 172.20.0.2
metadata:
namespace: config
type: KubernetesControlPlaneConfigs.config.talos.dev
id: apiserver-admission-control
version: 1
owner: config.K8sControlPlaneController
phase: running
created: 2022-02-22T20:28:21Z
updated: 2022-02-22T20:28:21Z
spec:
config:
- name: PodSecurity
configuration:
apiVersion: pod-security.admission.config.k8s.io/v1alpha1
defaults:
audit: restricted
audit-version: latest
enforce: baseline
enforce-version: latest
warn: restricted
warn-version: latest
exemptions:
namespaces:
- kube-system
runtimeClasses: []
usernames: []
kind: PodSecurityConfiguration
Usage
Create a deployment that satisfies the baseline policy but gives warnings on restricted policy:
$ kubectl create deployment nginx --image=nginx
Warning: would violate PodSecurity "restricted:latest": allowPrivilegeEscalation != false (container "nginx" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "nginx" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "nginx" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "nginx" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost")
deployment.apps/nginx created
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-85b98978db-j68l8 1/1 Running 0 2m3s
Create a daemonset which fails to meet requirements of the baseline policy:
apiVersion: apps/v1
kind: DaemonSet
metadata:
labels:
app: debug-container
name: debug-container
namespace: default
spec:
revisionHistoryLimit: 10
selector:
matchLabels:
app: debug-container
template:
metadata:
creationTimestamp: null
labels:
app: debug-container
spec:
containers:
- args:
- "360000"
command:
- /bin/sleep
image: ubuntu:latest
imagePullPolicy: IfNotPresent
name: debug-container
resources: {}
securityContext:
privileged: true
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirstWithHostNet
hostIPC: true
hostPID: true
hostNetwork: true
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
updateStrategy:
rollingUpdate:
maxSurge: 0
maxUnavailable: 1
type: RollingUpdate
$ kubectl apply -f debug.yaml
Warning: would violate PodSecurity "restricted:latest": host namespaces (hostNetwork=true, hostPID=true, hostIPC=true), privileged (container "debug-container" must not set securityContext.privileged=true), allowPrivilegeEscalation != false (container "debug-container" must set securityContext.allowPrivilegeEscalation=false), unrestricted capabilities (container "debug-container" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "debug-container" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "debug-container" must set securityContext.seccompProfile.type to "RuntimeDefault" or "Localhost")
daemonset.apps/debug-container created
Daemonset debug-container gets created, but no pods are scheduled:
$ kubectl get ds
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
debug-container 0 0 0 0 0 <none> 34s
Pod Security Admission plugin errors are in the daemonset events:
$ kubectl describe ds debug-container
...
Warning FailedCreate 92s daemonset-controller Error creating: pods "debug-container-kwzdj" is forbidden: violates PodSecurity "baseline:latest": host namespaces (hostNetwork=true, hostPID=true, hostIPC=true), privileged (container "debug-container" must not set securityContext.privileged=true)
Pod Security Admission configuration can also be overridden on a namespace level:
$ kubectl label ns default pod-security.kubernetes.io/enforce=privileged
namespace/default labeled
$ kubectl get ds
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
debug-container 2 2 0 2 0 <none> 4s
As enforce policy was updated to the privileged for the default namespace, debug-container is now successfully running.
6 - Storage
In Kubernetes, using storage in the right way is well-facilitated by the API.
However, unless you are running in a major public cloud, that API may not be hooked up to anything.
This frequently sends users down a rabbit hole of researching all the various options for storage backends for their platform, for Kubernetes, and for their workloads.
There are a lot of options out there, and it can be fairly bewildering.
For Talos, we try to limit the options somewhat to make the decision-making easier.
Public Cloud
If you are running on a major public cloud, use their block storage. It is easy and automatic.
Storage Clusters
Sidero Labs recommends having separate disks (apart from the Talos install disk) to be used for storage.
Redundancy, scaling capabilities, reliability, speed, maintenance load, and ease of use are all factors you must consider when managing your own storage.
Running a storage cluster can be a very good choice when managing your own storage, and there are two projects we recommend, depending on your situation.
If you need vast amounts of storage composed of more than a dozen or so disks, we recommend you use Rook to manage Ceph. Also, if you need both mount-once and mount-many capabilities, Ceph is your answer. Ceph also bundles in an S3-compatible object store. The down side of Ceph is that there are a lot of moving parts.
Please note that most people should never use mount-many semantics. NFS is pervasive because it is old and easy, not because it is a good idea. While it may seem like a convenience at first, there are all manner of locking, performance, change control, and reliability concerns inherent in any mount-many situation, so we strongly recommend you avoid this method.
If your storage needs are small enough to not need Ceph, use Mayastor.
Rook/Ceph
Ceph is the grandfather of open source storage clusters. It is big, has a lot of pieces, and will do just about anything. It scales better than almost any other system out there, open source or proprietary, being able to easily add and remove storage over time with no downtime, safely and easily. It comes bundled with RadosGW, an S3-compatible object store; CephFS, a NFS-like clustered filesystem; and RBD, a block storage system.
With the help of Rook, the vast majority of the complexity of Ceph is hidden away by a very robust operator, allowing you to control almost everything about your Ceph cluster from fairly simple Kubernetes CRDs.
So if Ceph is so great, why not use it for everything?
Ceph can be rather slow for small clusters. It relies heavily on CPUs and massive parallelisation to provide good cluster performance, so if you don’t have much of those dedicated to Ceph, it is not going to be well-optimised for you. Also, if your cluster is small, just running Ceph may eat up a significant amount of the resources you have available.
Troubleshooting Ceph can be difficult if you do not understand its architecture. There are lots of acronyms and the documentation assumes a fair level of knowledge. There are very good tools for inspection and debugging, but this is still frequently seen as a concern.
Mayastor
Mayastor is an OpenEBS project built in Rust utilising the modern NVMEoF system. (Despite the name, Mayastor does not require you to have NVME drives.) It is fast and lean but still cluster-oriented and cloud native. Unlike most of the other OpenEBS project, it is not built on the ancient iSCSI system.
Unlike Ceph, Mayastor is just a block store. It focuses on block storage and does it well. It is much less complicated to set up than Ceph, but you probably wouldn’t want to use it for more than a few dozen disks.
Mayastor is new, maybe too new. If you’re looking for something well-tested and battle-hardened, this is not it. However, if you’re looking for something lean, future-oriented, and simpler than Ceph, it might be a great choice.
Video Walkthrough
To see a live demo of this section, see the video below:
Prep Nodes
Either during initial cluster creation or on running worker nodes, several machine config values should be edited.
(This information is gathered from the Mayastor documentation.)
We need to set the vm.nr_hugepages sysctl and add openebs.io/engine=mayastor labels to the nodes which are meant to be storage nodes.
This can be done with talosctl patch machineconfig or via config patches during talosctl gen config.
Some examples are shown below: modify as needed.
Using gen config
talosctl gen config my-cluster https://mycluster.local:6443 --config-patch '[{"op": "add", "path": "/machine/sysctls", "value": {"vm.nr_hugepages": "1024"}}, {"op": "add", "path": "/machine/kubelet/extraArgs", "value": {"node-labels": "openebs.io/engine=mayastor"}}]'
Patching an existing node
talosctl patch --mode=no-reboot machineconfig -n <node ip> --patch '[{"op": "add", "path": "/machine/sysctls", "value": {"vm.nr_hugepages": "1024"}}, {"op": "add", "path": "/machine/kubelet/extraArgs", "value": {"node-labels": "openebs.io/engine=mayastor"}}]'
Note: If you are adding/updating the
vm.nr_hugepageson a node which already had theopenebs.io/engine=mayastorlabel set, you’d need to restart kubelet so that it picks up the new value, by issuing the following command
talosctl -n <node ip> service kubelet restart
Deploy Mayastor
Continue setting up Mayastor using the official documentation.
NFS
NFS is an old pack animal long past its prime. NFS is slow, has all kinds of bottlenecks involving contention, distributed locking, single points of service, and more. However, it is supported by a wide variety of systems. You don’t want to use it unless you have to, but unfortunately, that “have to” is too frequent.
The NFS client is part of the kubelet image maintained by the Talos team.
This means that the version installed in your running kubelet is the version of NFS supported by Talos.
You can reduce some of the contention problems by parceling Persistent Volumes from separate underlying directories.
Object storage
Ceph comes with an S3-compatible object store, but there are other options, as well. These can often be built on top of other storage backends. For instance, you may have your block storage running with Mayastor but assign a Pod a large Persistent Volume to serve your object store.
One of the most popular open source add-on object stores is MinIO.
Others (iSCSI)
The most common remaining systems involve iSCSI in one form or another. These include the original OpenEBS, Rancher’s Longhorn, and many proprietary systems. Unfortunately, Talos does not support iSCSI-based systems. iSCSI in Linux is facilitated by open-iscsi. This system was designed long before containers caught on, and it is not well suited to the task, especially when coupled with a read-only host operating system.
One day, we hope to work out a solution for facilitating iSCSI-based systems, but this is not yet available.