added some formatting
This commit is contained in:
1
frontend/.prettierignore
Normal file
1
frontend/.prettierignore
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@ -0,0 +1 @@
|
||||
src/assets
|
||||
@ -10,4 +10,4 @@
|
||||
"arrowParens": "always",
|
||||
"endOfLine": "lf",
|
||||
"bracketSpacing": true
|
||||
}
|
||||
}
|
||||
|
||||
@ -19,10 +19,7 @@ export default tseslint.config(
|
||||
},
|
||||
rules: {
|
||||
...reactHooks.configs.recommended.rules,
|
||||
'react-refresh/only-export-components': [
|
||||
'warn',
|
||||
{ allowConstantExport: true },
|
||||
],
|
||||
},
|
||||
'react-refresh/only-export-components': ['warn', { allowConstantExport: true }],
|
||||
},
|
||||
}
|
||||
)
|
||||
|
||||
@ -1,43 +0,0 @@
|
||||
<svg viewBox="0 0 600 400" xmlns="http://www.w3.org/2000/svg">
|
||||
<!-- Title -->
|
||||
<text x="300" y="30" text-anchor="middle" font-size="20" font-weight="bold">DaemonSet</text>
|
||||
|
||||
<!-- DaemonSet Controller -->
|
||||
<rect x="250" y="50" width="100" height="50" fill="#4a9eda" rx="5"/>
|
||||
<text x="300" y="80" text-anchor="middle" fill="white">DaemonSet</text>
|
||||
|
||||
<!-- Node 1 -->
|
||||
<rect x="50" y="150" width="150" height="200" fill="#f0f0f0" rx="5" stroke="#666"/>
|
||||
<text x="125" y="180" text-anchor="middle" font-weight="bold">Node 1</text>
|
||||
<g transform="translate(85,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<!-- Node 2 -->
|
||||
<rect x="225" y="150" width="150" height="200" fill="#f0f0f0" rx="5" stroke="#666"/>
|
||||
<text x="300" y="180" text-anchor="middle" font-weight="bold">Node 2</text>
|
||||
<g transform="translate(260,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<!-- Node 3 -->
|
||||
<rect x="400" y="150" width="150" height="200" fill="#f0f0f0" rx="5" stroke="#666"/>
|
||||
<text x="475" y="180" text-anchor="middle" font-weight="bold">Node 3</text>
|
||||
<g transform="translate(435,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<!-- Connecting Lines -->
|
||||
<path d="M300 100 L125 150" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 100 L300 150" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 100 L475 150" stroke="black" stroke-width="2"/>
|
||||
</svg>
|
||||
|
Before Width: | Height: | Size: 2.0 KiB |
@ -1,62 +0,0 @@
|
||||
## Deployment
|
||||
|
||||
A `Deployment` manages a set pod Pods to run an application workload, usually one that does not maintain **state**. A `Deployment` provides declarative updates for Pods and ReplicaSets. When we describe a desired state in a `Deployment`, the Deployment controller changes the actual state to the desired state at a controlled rate.
|
||||
|
||||
![[deployment-diagram.svg]]
|
||||
In Kubernetes, a `Deployment` is limited to containing a single pod template specification (PodSpec). This template serves as the blueprint for creating identical pods. The Deployment controller ensures that the desired number of replicas of this pod template are maintained and running at all times.
|
||||
|
||||
Within this single pod template, developers have the flexibility to define either a single container or multiple containers that will run within each pod. When multiple containers are specified, they are co-located and managed together as a single unit within the pod.
|
||||
|
||||
The number of replicas specified in the `Deployment` configuration determines how many identical pods will be created, each containing the same set of defined containers. For example, if a `Deployment` specifies three replicas of a pod template that contains two containers, Kubernetes will create three identical pods, each running both containers.
|
||||
|
||||
|
||||
## DaemonSet
|
||||
|
||||
A ``DaemonSet`` is a Kubernetes resource designed to ensure that a specific pod runs on every node within a cluster, making it ideal for node-level operations and infrastructure services. These pods typically provide essential node-local facilities that support the cluster's fundamental operations, such as:
|
||||
|
||||
- Network management tools
|
||||
- Log collection systems
|
||||
- Storage management solutions
|
||||
- Monitoring agents
|
||||
![[daemonset-diagram.svg]]
|
||||
Like Deployments, `DaemonSet`s are constrained to a single pod template specification (PodSpec). Within this template, administrators can define one or multiple containers that will run together in each pod. The key distinction from Deployments is that `DaemonSet`s automatically manage pod distribution, ensuring exactly one pod instance runs on each cluster node without requiring explicit replica configuration.
|
||||
|
||||
This architecture makes `DaemonSet`s particularly suitable for implementing cluster-wide infrastructure services that need to operate consistently across all nodes. By automatically scheduling pods on both existing nodes and any new nodes added to the cluster, `DaemonSet`s maintain uniform functionality throughout the cluster's infrastructure.
|
||||
|
||||
|
||||
## StatefulSet
|
||||
|
||||
A `StatefulSet` is a Kubernetes resource designed to manage stateful applications that require stable network identities, persistent storage, and ordered deployment and scaling. Unlike Deployments, which treat pods as interchangeable units, `StatefulSet`s maintain a unique, persistent identity for each pod, making them ideal for applications such as:
|
||||
|
||||
- Distributed databases
|
||||
- Message brokers
|
||||
- Applications requiring stable network identifiers
|
||||
- Systems needing ordered deployment and scaling
|
||||
|
||||
![[statefulset-diagram.svg]]
|
||||
Like Deployments and `DaemonSet`s, `StatefulSet`s are limited to a single pod template specification (PodSpec), within which administrators can define one or multiple containers. However, `StatefulSet`s possess distinct characteristics:
|
||||
|
||||
- Pods receive predictable names and persistent identifiers (e.g., app-0, app-1, app-2)
|
||||
- Pod creation, scaling, and deletion occur in a predetermined order
|
||||
- Each pod can be associated with its own persistent storage volume. Whereas in Deployment the all the pods share the same persistent storage.
|
||||
- Network identities remain stable across pod rescheduling
|
||||
|
||||
The ordered nature of `StatefulSet`s ensures that pods are created sequentially (0 to N), and scaled down in reverse order (N to 0), making them suitable for applications where pod ordering and uniqueness are crucial for proper operation. A following pod will not launch until the current Pod reaches a running and ready state.
|
||||
|
||||
|
||||
## Comparison Between Deployment, DaemonSet, and StatefulSet
|
||||
|
||||
| Feature/Aspect | Deployment | DaemonSet | StatefulSet |
|
||||
|---------------|------------|----------|-------------|
|
||||
| **Primary Use Case** | General purpose workloads, stateless applications | Node-level operations, infrastructure services | Stateful applications, databases |
|
||||
| **Pod Identity** | Pods are identical and interchangeable | Pods are identical but node-specific | Pods have unique, persistent identities (pod-0, pod-1) |
|
||||
| **Scaling** | Manual or automatic scaling with specified number of replicas | Automatic - one pod per node | Manual scaling with ordered pod creation/deletion |
|
||||
| **Pod Template** | Single PodSpec | Single PodSpec | Single PodSpec |
|
||||
| **Pod Names** | Random (e.g., app-7849d89d47-xxxx) | Random with node affinity | Predictable, ordered (e.g., app-0, app-1) |
|
||||
| **Storage** | Can use PVC (shared among all pods) | Can use PVC (one per node) | Unique PVC per pod using volumeClaimTemplates |
|
||||
| **Network Identity** | Service load balances to any pod | Node-level networking possible | Stable network identity per pod |
|
||||
| **Update Strategy** | Rolling update by default | Rolling update on each node | Ordered update from N-1 to 0 |
|
||||
| **Common Examples** | - Web applications<br>- Microservices<br>- API servers | - Monitoring agents<br>- Log collectors<br>- Network plugins | - Databases<br>- Message queues<br>- Distributed systems |
|
||||
| **Scale Down Order** | Random | From specific nodes | Reverse order (N to 0) |
|
||||
| **Node Placement** | Any available nodes | One pod per node | Any available nodes (with ordering) |
|
||||
| **Replica Configuration** | `.spec.replicas` field | No replica field (automatic) | `.spec.replicas` field
|
||||
@ -1,40 +0,0 @@
|
||||
<svg viewBox="0 0 600 300" xmlns="http://www.w3.org/2000/svg">
|
||||
<!-- Title -->
|
||||
<text x="300" y="30" text-anchor="middle" font-size="20" font-weight="bold">Deployment</text>
|
||||
|
||||
<!-- Deployment Controller -->
|
||||
<rect x="250" y="50" width="100" height="50" fill="#4a9eda" rx="5"/>
|
||||
<text x="300" y="80" text-anchor="middle" fill="white">Deployment</text>
|
||||
|
||||
<!-- ReplicaSet -->
|
||||
<rect x="250" y="120" width="100" height="40" fill="#67b246" rx="5"/>
|
||||
<text x="300" y="145" text-anchor="middle" fill="white">ReplicaSet</text>
|
||||
|
||||
<!-- Pods -->
|
||||
<g transform="translate(100,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod 1</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<g transform="translate(260,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod 2</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<g transform="translate(420,200)">
|
||||
<rect width="80" height="60" fill="#f2d864" rx="5"/>
|
||||
<text x="40" y="25" text-anchor="middle">Pod 3</text>
|
||||
<rect x="10" y="30" width="60" height="20" fill="#b4b4b4" rx="3"/>
|
||||
<text x="40" y="45" text-anchor="middle" font-size="12">Container</text>
|
||||
</g>
|
||||
|
||||
<!-- Connecting Lines -->
|
||||
<path d="M300 100 L300 120" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 160 L140 200" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 160 L300 200" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 160 L460 200" stroke="black" stroke-width="2"/>
|
||||
</svg>
|
||||
|
Before Width: | Height: | Size: 1.7 KiB |
@ -1,50 +0,0 @@
|
||||
<svg viewBox="0 0 600 400" xmlns="http://www.w3.org/2000/svg">
|
||||
<!-- Title -->
|
||||
<text x="300" y="30" text-anchor="middle" font-size="20" font-weight="bold">StatefulSet</text>
|
||||
|
||||
<!-- StatefulSet Controller -->
|
||||
<rect x="250" y="50" width="100" height="50" fill="#4a9eda" rx="5"/>
|
||||
<text x="300" y="80" text-anchor="middle" fill="white">StatefulSet</text>
|
||||
|
||||
<!-- Pods with PVCs -->
|
||||
<g transform="translate(50,150)">
|
||||
<rect width="150" height="100" fill="#f2d864" rx="5"/>
|
||||
<text x="75" y="30" text-anchor="middle" font-weight="bold">Pod-0</text>
|
||||
<rect x="20" y="40" width="110" height="25" fill="#b4b4b4" rx="3"/>
|
||||
<text x="75" y="57" text-anchor="middle" font-size="12">Container</text>
|
||||
<rect x="20" y="70" width="110" height="20" fill="#67b246" rx="3"/>
|
||||
<text x="75" y="84" text-anchor="middle" font-size="12">PVC-0</text>
|
||||
</g>
|
||||
|
||||
<g transform="translate(225,150)">
|
||||
<rect width="150" height="100" fill="#f2d864" rx="5"/>
|
||||
<text x="75" y="30" text-anchor="middle" font-weight="bold">Pod-1</text>
|
||||
<rect x="20" y="40" width="110" height="25" fill="#b4b4b4" rx="3"/>
|
||||
<text x="75" y="57" text-anchor="middle" font-size="12">Container</text>
|
||||
<rect x="20" y="70" width="110" height="20" fill="#67b246" rx="3"/>
|
||||
<text x="75" y="84" text-anchor="middle" font-size="12">PVC-1</text>
|
||||
</g>
|
||||
|
||||
<g transform="translate(400,150)">
|
||||
<rect width="150" height="100" fill="#f2d864" rx="5"/>
|
||||
<text x="75" y="30" text-anchor="middle" font-weight="bold">Pod-2</text>
|
||||
<rect x="20" y="40" width="110" height="25" fill="#b4b4b4" rx="3"/>
|
||||
<text x="75" y="57" text-anchor="middle" font-size="12">Container</text>
|
||||
<rect x="20" y="70" width="110" height="20" fill="#67b246" rx="3"/>
|
||||
<text x="75" y="84" text-anchor="middle" font-size="12">PVC-2</text>
|
||||
</g>
|
||||
|
||||
<!-- Service Headless -->
|
||||
<rect x="50" y="300" width="500" height="40" fill="#f08d49" rx="5"/>
|
||||
<text x="300" y="325" text-anchor="middle" fill="white">Headless Service (DNS: pod-{0,1,2}.service)</text>
|
||||
|
||||
<!-- Connecting Lines -->
|
||||
<path d="M300 100 L125 150" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 100 L300 150" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 100 L475 150" stroke="black" stroke-width="2"/>
|
||||
|
||||
<!-- Service Connections -->
|
||||
<path d="M125 250 L125 300" stroke="black" stroke-width="2"/>
|
||||
<path d="M300 250 L300 300" stroke="black" stroke-width="2"/>
|
||||
<path d="M475 250 L475 300" stroke="black" stroke-width="2"/>
|
||||
</svg>
|
||||
|
Before Width: | Height: | Size: 2.4 KiB |
@ -1,399 +0,0 @@
|
||||
## Introduction
|
||||
|
||||
A pod specification can define one or more volumes and specify where they should be mounted. Each volume requires a name, a type, and a mount point. *The same volume can be shared across multiple containers within a pod, enabling container-to-container communication.* Volumes with the `ReadWriteMany` access mode can also be shared across multiple pods, allowing each pod to write to the volume. However, there is no built-in mechanism for concurrency control, which increases the risk of data corruption unless external locking mechanisms are implemented.
|
||||
|
||||
A particular access mode is part of a Pod request. As a request, the user may be granted more, but not less access, though a direct match is attempted first. The cluster groups volumes with the same mode together, then sorts volumes by size, from smallest to largest. The claim is checked against each in that access mode group, until a volume of sufficient size matches. The three access modes are:
|
||||
|
||||
- `ReadWriteOnce`, which allows read-write by a single node
|
||||
- `ReadOnlyMany`, which allows read-only by multiple nodes
|
||||
- `ReadWriteMany`, which allows read-write by many nodes
|
||||
|
||||
Only a single pod can write to a `ReadWriteOnce` volume. Any additional pods, regardless of whether they are on the same node or a different node, will be unable to write to the volume and will fail to become ready, resulting in a `FailedAttachVolume` error.
|
||||
|
||||
When a volume is requested, the local kubelet uses the **kubelet_pods.go** script to map the raw devices, determine and make the mount point for the container, then create the symbolic link on the host node `filesystem` to associate the storage to the container. The API server makes a request for the storage to the **`StorageClass`** plugin, but the specifics of the requests to the `backend` storage depend on the plugin in use.
|
||||
|
||||
If a request for a particular **`StorageClass`** was not made, then the only parameters used will be access mode and size. The volume could come from any of the storage types available, and there is no configuration to determine which of the available ones will be used.
|
||||
|
||||
## Volume Spec
|
||||
|
||||
Here is an example volume spec:
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: Pod
|
||||
metadata:
|
||||
name: fordpinto
|
||||
namespace: default
|
||||
spec:
|
||||
containers:
|
||||
- image: simpleapp
|
||||
name: gastank
|
||||
command:
|
||||
- sleep
|
||||
- "3600"
|
||||
volumeMounts:
|
||||
- mountPath: /scratch
|
||||
name: scratch-volume
|
||||
volumes:
|
||||
- name: scratch-volume
|
||||
emptyDir: {}
|
||||
```
|
||||
|
||||
One of the many types of storage available is an `emptyDir`. The kubelet will create the directory in the container, but not mount any storage. Any data created is written to the shared container space. As a result, it would not be persistent storage. When the `Pod` is destroyed, the directory would be deleted along with the container.
|
||||
|
||||
## Volume Types
|
||||
|
||||
Ref: https://kubernetes.io/docs/concepts/storage/volumes/
|
||||
|
||||
There are various types of volumes available in Kubernetes, each with its own advantages and limitations. Some are local to the node, while others rely on network-based resources.
|
||||
|
||||
For example, in cloud environments like GCE or AWS, you can use `GCEPersistentDisk` or `awsElasticBlockStore` to mount GCE or EBS disks in your Pods. This requires preconfigured accounts and appropriate permissions.
|
||||
|
||||
Local volumes such as `emptyDir` and `hostPath` are simple to use:
|
||||
|
||||
- **`emptyDir`**: Creates a temporary directory for the Pod. It is deleted when the Pod stops but recreated when the container restarts.
|
||||
- **`hostPath`**: Mounts a resource from the node’s `filesystem`, such as a directory, file, socket, or block device. These resources must already exist on the host unless you use `DirectoryOrCreate` or `FileOrCreate`, which create the resources if they are missing.
|
||||
|
||||
For shared access across multiple Pods, network-based options like **NFS (Network File System)** or **iSCSI (Internet Small Computer System Interface)** are good choices.
|
||||
|
||||
In addition to these, Kubernetes supports many other volume types, including `azureDisk`, `azureFile`, `csi`, `local`, `secret`, `persistentVolumeClaim`, and more. The **Container Storage Interface (CSI)** adds even more flexibility by enabling custom storage plugins without modifying Kubernetes itself. This has led to the deprecation and removal of many older "in-tree" storage drivers, with their functionality redirected to CSI drivers.
|
||||
|
||||
_Note: Ensure you verify volume compatibility and life-cycle when choosing a type, as older in-tree drivers may no longer be supported in newer Kubernetes versions._
|
||||
|
||||
## Shared Volume example
|
||||
|
||||
The volumes attached to a pod can be shared across all the containers within a pod even with `ReadWriteOnce` access. Here is an example YAML file with two containers sharing the same volume.
|
||||
|
||||
```yaml
|
||||
**containers:
|
||||
- name: alphacont
|
||||
image: busybox
|
||||
volumeMounts:
|
||||
- mountPath: /alphadir
|
||||
name: sharevol
|
||||
- name: betacont
|
||||
image: busybox
|
||||
volumeMounts:
|
||||
- mountPath: /betadir
|
||||
name: sharevol
|
||||
volumes:
|
||||
- name: sharevol
|
||||
emptyDir: {}**
|
||||
```
|
||||
|
||||
Now, take a look at the following commands and outputs:
|
||||
|
||||
```bash
|
||||
$ kubectl exec -ti exampleA -c betacont -- touch /betadir/foobar
|
||||
$ kubectl exec -ti exampleA -c alphacont -- ls -l /alphadir
|
||||
|
||||
total 0
|
||||
-rw-r--r-- 1 root root 0 Nov 19 16:26 foobar
|
||||
```
|
||||
|
||||
You could use `emptyDir` or `hostPath` easily, since those types do not require any additional setup, and will work in your Kubernetes cluster.
|
||||
|
||||
Note that one container (**betacont**) wrote, and the other container (**alphacont**) had immediate access to the data. There is nothing to keep the containers from overwriting the other's data. Locking or versioning considerations must be part of the containerized application to avoid corruption.
|
||||
|
||||
## Persistent Volumes and Claims
|
||||
|
||||
A persistent volume (pv) is a storage abstraction used to retain data longer than the Pod using it. `Pods` define a volume of type `persistentVolumeClaim` (pvc) with various parameters for size and possibly the type of backend storage known as `storageClass`. The cluster then attaches the `persistentVolume`.
|
||||
|
||||
There are several phases to persistent storage.
|
||||
1. Provision: **Provisioning** can be from PVs created in advance by the cluster administrator, or requested from a dynamic source, such as the cloud provider.
|
||||
2. Bind: **Provisioning** can be from PVs created in advance by the cluster administrator, or requested from a dynamic source, such as the cloud provider.
|
||||
3. Use: **Provisioning** can be from PVs created in advance by the cluster administrator, or requested from a dynamic source, such as the cloud provider.
|
||||
4. Release: **Provisioning** can be from PVs created in advance by the cluster administrator, or requested from a dynamic source, such as the cloud provider.
|
||||
5. Reclaim: The **reclaim** phase has three options:
|
||||
- **Retain**, which keeps the data intact, allowing for an administrator to handle the storage and data.
|
||||
- **Delete** tells the volume plugin to delete the API object, as well as the storage behind it.
|
||||
- The **Recycle** option runs an **rm -rf /mountpoint** and then makes it available to a new claim. With the stability of dynamic provisioning, the Recycle option is planned to be deprecated.
|
||||
|
||||
We can check the pvc and pv in our cluster with the following kubectl commands:
|
||||
|
||||
```bash
|
||||
kubectl get pvc -n <namespace>
|
||||
kubectl get pv -n <namespace>
|
||||
```
|
||||
|
||||
### Persistent Volume
|
||||
|
||||
The following example shows a basic declaration of a Persistent Volume using the hostPath type. It will provision a 10Gi storage in one of the nodes in the cluster.
|
||||
|
||||
```yaml
|
||||
kind: PersistentVolume
|
||||
apiVersion: v1
|
||||
metadata:
|
||||
name: 10Gpv01
|
||||
labels:
|
||||
type: local** **spec:
|
||||
capacity:
|
||||
storage: 10Gi
|
||||
accessModes:
|
||||
- ReadWriteOnce
|
||||
hostPath:
|
||||
path: "/somepath/data01"
|
||||
```
|
||||
|
||||
Each type will have its own configuration settings. For example, an already created `Ceph` or `GCE` Persistent Disk would not need to be configured, but could be claimed from the provisioner.
|
||||
|
||||
One thing to note is that the Persistent Volumes are not a namespaces object, but the persistent volume claims are.
|
||||
|
||||
The use of locally attached storage has been graduated to a stable feature. This feature is often used as part of distributed file systems and databases.
|
||||
|
||||
### Persistent Volume Claim
|
||||
|
||||
With persistent volume created in the cluster, we can then write a manifest for a claim, and use that claim in your pod definition. In the pod, the volumes uses the `persistentVolumeClaim`.
|
||||
|
||||
```yaml
|
||||
kind: PersistentVolumeClaim
|
||||
apiVersion: v1
|
||||
metadata:
|
||||
name: myclaim
|
||||
spec:
|
||||
accessModes:
|
||||
- ReadWriteOnce
|
||||
resources:
|
||||
requests:
|
||||
storage: 8GI
|
||||
```
|
||||
|
||||
And, in the pod we can add the volume like this:
|
||||
|
||||
```yaml
|
||||
spec:
|
||||
containers:
|
||||
....
|
||||
volumes:
|
||||
- name: test-volume
|
||||
persistentVolumeClaim:
|
||||
claimName: myclaim
|
||||
```
|
||||
|
||||
Or, in more complex form with more config,
|
||||
|
||||
```yaml
|
||||
volumeMounts:
|
||||
- name: Cephpd
|
||||
mountPath: /data/rbd
|
||||
volumes:
|
||||
- name: rbdpd
|
||||
rbd:
|
||||
monitors:
|
||||
- '10.19.14.22:6789'
|
||||
- '10.19.14.23:6789'
|
||||
- '10.19.14.24:6789'
|
||||
pool: k8s
|
||||
image: client
|
||||
fsType: ext4
|
||||
readOnly: true
|
||||
user: admin
|
||||
keyring: /etc/ceph/keyring
|
||||
```
|
||||
|
||||
## Dynamic Provisioning
|
||||
|
||||
While handling volumes with a persistent volume definition and abstracting the storage provider using a claim is powerful, a cluster administrator still needs to create those volumes in the first place. The dynamic provisioning allows for the cluster to request storage from an exterior, pre-configured source. API calls made by the appropriate plugin allow for a wide range of dynamic storage class.
|
||||
|
||||
The **StorageClass** API resource allows an administrator to define a persistent volume provisioner of a certain type, passing storage-specific parameters.
|
||||
|
||||
With a **StorageClass** created, a user can request a claim, which the API Server fills via auto-provisioning. The resource will also be reclaimed as configured by the provider. AWS and GCE are common choices for dynamic storage, but other options exist, such as a Ceph cluster or iSCSI. Single, default class is possible via annotation.
|
||||
|
||||
Here is an example of a `StorageClass` using Longhorn:
|
||||
|
||||
```yaml
|
||||
allowVolumeExpansion: true
|
||||
apiVersion: storage.k8s.io/v1
|
||||
kind: StorageClass
|
||||
metadata:
|
||||
storageclass.kubernetes.io/is-default-class: "true"
|
||||
name: longhorn
|
||||
parameters:
|
||||
dataLocality: disabled
|
||||
disableRevisionCounter: "true"
|
||||
fromBackup: ""
|
||||
fsType: ext4
|
||||
numberOfReplicas: "1"
|
||||
staleReplicaTimeout: "30"
|
||||
unmapMarkSnapChainRemoved: ignored
|
||||
provisioner: driver.longhorn.io
|
||||
reclaimPolicy: Delete
|
||||
volumeBindingMode: Immediate
|
||||
```
|
||||
|
||||
## Secrets
|
||||
|
||||
Secret is a type of Kubernetes volume and an object that contains small amount of sensitive information such as a password or TLS private key. Using secret mean, the confidential information does not need to be included in the pods manifest or application code.
|
||||
|
||||
Secrets can be encoded manually or via kubectl create secret.
|
||||
|
||||
```bash
|
||||
$kubectl create secret generic postgres --from-literal=password=root
|
||||
```
|
||||
|
||||
A secret is not encrypted, only base64-encoded by default. It is possible to also encypt secret but for that an `EncryptionConfiguration` with a key and proper identity. Then the kube-apiserver needs teh --encryption-provider-config flag set to a provider such as ksm or aescbc. Once this is enabled, all the secrets need to be recreated.
|
||||
|
||||
Here is an example how to use secret in a podSpec
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: Pod
|
||||
metadata:
|
||||
name: mypod
|
||||
spec:
|
||||
containers:
|
||||
- name: mypod
|
||||
image: redis
|
||||
env:
|
||||
- name: SECRET_KEY <- Here secret is read and saved to env variable
|
||||
valueFrom:
|
||||
secretKeyRef:
|
||||
name: mysecret
|
||||
key: username
|
||||
volumeMounts: <- Here secret is mounted to a file called /etc/foo
|
||||
- name: foo
|
||||
mountPath: "/etc/foo"
|
||||
readOnly: true
|
||||
volumes:
|
||||
- name: foo
|
||||
secret:
|
||||
secretName: mysecret
|
||||
optional: true
|
||||
```
|
||||
|
||||
There is no limit how many number of secrets can be used, but there is a 1MB limit to their size. Each secret occupies memory, along with other API objects, so very large number of secrets could deplete memory on a host.
|
||||
|
||||
They are stored in the `tmpfs` storage on the host node, and are only sent to the host running the `Pod`.
|
||||
|
||||
Kubernetes provides several built-in types of secrets for some common usage scenarios.
|
||||
|
||||
|Built-in Type|Usage|
|
||||
|---|---|
|
||||
|`Opaque`|arbitrary user-defined data|
|
||||
|`kubernetes.io/service-account-token`|ServiceAccount token|
|
||||
|`kubernetes.io/dockercfg`|serialized `~/.dockercfg` file|
|
||||
|`kubernetes.io/dockerconfigjson`|serialized `~/.docker/config.json` file|
|
||||
|`kubernetes.io/basic-auth`|credentials for basic authentication|
|
||||
|`kubernetes.io/ssh-auth`|credentials for SSH authentication|
|
||||
|`kubernetes.io/tls`|data for a TLS client or server|
|
||||
|`bootstrap.kubernetes.io/token`|bootstrap token data
|
||||
|
||||
## ConfigMaps
|
||||
|
||||
A `ConfigMap` is akin to a `Secret`, with the distinction that its data is not encoded. In alignment with Kubernetes' principle of decoupling, utilizing a `ConfigMap` separates a container image from its configuration artifacts. This separation ensures that the container does not need to be rebuilt each time the configuration information is modified; instead, the container can simply reference the values stored in the `ConfigMap`.
|
||||
|
||||
`ConfigMap` stores data in key-value pairs or as plain configuration files in various formats. The data can be populated from a collection of files, all files within a directory, or from literal values.
|
||||
|
||||
A `ConfigMap` can be consumed in multiple ways. For instance, a container can use the data as environment variables, or the values can be passed to commands within a pod. Additionally, a volume or a file within a volume can be created, with options for different names and specific access modes. Furthermore, cluster components such as controllers can utilize the data stored in a `ConfigMap`.
|
||||
|
||||
Here is a summary of ways `configMap` can be consumed:
|
||||
|
||||
1. Inside a container command and args
|
||||
2. Environment variables for a container
|
||||
3. Add a file in read-only volume, for the application to read
|
||||
4. Write code to run inside the Pod that uses the Kubernetes API to read a `ConfigMap`
|
||||
|
||||
Here is an example of `configMap` containing whole file created from literal.
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
name: wireguard-config
|
||||
namespace: media # Adjust the namespace accordingly
|
||||
data:
|
||||
wg0.conf: |
|
||||
[Interface]
|
||||
Address = ipv4/32,ipv6/128
|
||||
PrivateKey = notarealkey
|
||||
MTU = 1320
|
||||
DNS = 10.128.0.1, fd7d:76ee:e68f:a993::1
|
||||
|
||||
[Peer]
|
||||
PublicKey = fake
|
||||
PresharedKey = fake
|
||||
Endpoint = asia.vpn.fake.org:1637
|
||||
AllowedIPs = 0.0.0.0/0,::/0
|
||||
PersistentKeepalive = 15
|
||||
```
|
||||
|
||||
Here is an example, how this value is used in `deployment`.
|
||||
|
||||
```yaml
|
||||
volumeMounts:
|
||||
- name: wireguard-config
|
||||
mountPath: /config/wg_confs <- The wg0.conf file path will be like: /config/wg_confs/wg0.conf
|
||||
-------------------------
|
||||
volumes:
|
||||
- name: wireguard-config
|
||||
configMap:
|
||||
name: wireguard-config
|
||||
```
|
||||
|
||||
Here is an example of `configMap` storing data as key-value pair.
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
name: game-demo
|
||||
data:
|
||||
# property-like keys; each key maps to a simple value
|
||||
player_initial_lives: "3"
|
||||
ui_properties_file_name: "user-interface.properties"
|
||||
|
||||
# file-like keys
|
||||
game.properties: |
|
||||
enemy.types=aliens,monsters
|
||||
player.maximum-lives=5
|
||||
user-interface.properties: |
|
||||
color.good=purple
|
||||
color.bad=yellow
|
||||
allow.textmode=true
|
||||
```
|
||||
|
||||
And here the `configMap` values are consumed in two different ways.
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: Pod
|
||||
metadata:
|
||||
name: configmap-demo-pod
|
||||
spec:
|
||||
containers:
|
||||
- name: demo
|
||||
image: alpine
|
||||
command: ["sleep", "3600"]
|
||||
env:
|
||||
# Define the environment variable
|
||||
- name: PLAYER_INITIAL_LIVES # Notice that the case is different here
|
||||
# from the key name in the ConfigMap.
|
||||
valueFrom:
|
||||
configMapKeyRef:
|
||||
name: game-demo # The ConfigMap this value comes from.
|
||||
key: player_initial_lives # The key to fetch.
|
||||
- name: UI_PROPERTIES_FILE_NAME
|
||||
valueFrom:
|
||||
configMapKeyRef:
|
||||
name: game-demo
|
||||
key: ui_properties_file_name
|
||||
volumeMounts:
|
||||
- name: config
|
||||
mountPath: "/config"
|
||||
readOnly: true
|
||||
volumes:
|
||||
# You set volumes at the Pod level, then mount them into containers inside that Pod
|
||||
- name: config
|
||||
configMap:
|
||||
# Provide the name of the ConfigMap you want to mount.
|
||||
name: game-demo
|
||||
# An array of keys from the ConfigMap to create as files
|
||||
items:
|
||||
- key: "game.properties"
|
||||
path: "game.properties"
|
||||
- key: "user-interface.properties"
|
||||
path: "user-interface.properties"
|
||||
```
|
||||
|
||||
A ConfigMap doesn't differentiate between single line property values and multi-line file-like values. What matters is how `Pods` and other objects consume those values.
|
||||
|
||||
For this example, defining a volume and mounting it inside the `demo` container as `/config` creates two files, `/config/game.properties` and `/config/user-interface.properties`, even though there are four keys in the `ConfigMap`. This is because the Pod definition specifies an `items` array in the `volumes` section. If we omit the `items` array entirely, every key in the `ConfigMap` becomes a file with the same name as the key, and we get 4 files (player_initial_lives, ui_properties_file_name, game.properties, user-interface.properties).
|
||||
@ -51,7 +51,7 @@ const Navbar: React.FC<NavProps> = ({ toggleDarkMode, darkMode }) => {
|
||||
return (
|
||||
<div className="w-full flex justify-center">
|
||||
<nav className="py-5 mb-6 flex justify-between dark:text-white w-full max-w-5xl px-4">
|
||||
<Tooltip label={copyText} position='bottom'>
|
||||
<Tooltip label={copyText} position="bottom">
|
||||
<button
|
||||
onClick={handleCopyEmail}
|
||||
className="flex items-center space-x-2 hover:bg-gray-100 dark:hover:bg-gray-800 px-3 py-2 rounded-lg transition-colors duration-200 group relative"
|
||||
@ -72,7 +72,7 @@ const Navbar: React.FC<NavProps> = ({ toggleDarkMode, darkMode }) => {
|
||||
className="transition ease-in-out delay-50 duration-100 cursor-pointer"
|
||||
onClick={toggleDarkMode}
|
||||
>
|
||||
<Tooltip label={darkMode ? 'Light Mode' : 'Dark Mode'} position='bottom'>
|
||||
<Tooltip label={darkMode ? 'Light Mode' : 'Dark Mode'} position="bottom">
|
||||
<div className="flex items-center space-x-2 mr-4">
|
||||
{darkMode ? (
|
||||
<Sun className="text-amber-400 hover:scale-110" size={30} />
|
||||
@ -83,7 +83,7 @@ const Navbar: React.FC<NavProps> = ({ toggleDarkMode, darkMode }) => {
|
||||
</Tooltip>
|
||||
</li>
|
||||
<li className="transition ease-in-out delay-50 duration-100">
|
||||
<Tooltip label="Resume" position='bottom'>
|
||||
<Tooltip label="Resume" position="bottom">
|
||||
<a
|
||||
className="text-white flex items-center space-x-2 ml-4"
|
||||
href={RESUME}
|
||||
|
||||
@ -11,15 +11,13 @@ export const Tooltip: React.FC<TooltipProps> = ({ children, label, position }) =
|
||||
left: 'right-full top-1/2 -translate-y-1/2',
|
||||
right: 'left-full top-1/2 -translate-y-1/2',
|
||||
}
|
||||
const tooltipPosition:string = tooltipStyles[position]
|
||||
const tooltipPosition: string = tooltipStyles[position]
|
||||
const tooltipClass = `pointer-events-none absolute mt-2 whitespace-nowrap rounded bg-slate-800 px-2 py-1 text-xs text-slate-100 opacity-0 transition before:absolute before:left-1/2 before:top-full before:-translate-x-1/2 before:border-4 before:border-transparent before:border-t-slate-800 before:content-[''] group-hover:opacity-100 ${tooltipPosition}`
|
||||
|
||||
return (
|
||||
<div className="group relative">
|
||||
{children}
|
||||
<span className={tooltipClass}>
|
||||
{label}
|
||||
</span>
|
||||
<span className={tooltipClass}>{label}</span>
|
||||
</div>
|
||||
)
|
||||
}
|
||||
|
||||
@ -1,10 +1,7 @@
|
||||
/** @type {import('tailwindcss').Config} */
|
||||
export default {
|
||||
darkMode: 'class',
|
||||
content: [
|
||||
"./index.html",
|
||||
"./src/**/*.{js,ts,jsx,tsx}",
|
||||
],
|
||||
content: ['./index.html', './src/**/*.{js,ts,jsx,tsx}'],
|
||||
theme: {
|
||||
extend: {},
|
||||
},
|
||||
|
||||
@ -1,7 +1,4 @@
|
||||
{
|
||||
"files": [],
|
||||
"references": [
|
||||
{ "path": "./tsconfig.app.json" },
|
||||
{ "path": "./tsconfig.node.json" }
|
||||
]
|
||||
"references": [{ "path": "./tsconfig.app.json" }, { "path": "./tsconfig.node.json" }]
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user