Ceph Persistent Storage for Kubernetes with Cephfs
Kubernetes is a prominent open-source orchestration platform. Individuals use it to deploy, manage, and scale applications. It is often challenging to manage stateful applications on this platform, especially those having heavy databases. Ceph is a robust distributed storage system that comes to the rescue. This open-source storage platform is known for its reliability, performance, and scalability. This blog post guides you on how to use Ceph persistent storage for Kubernetes with Cephfs. So let us learn the process step-by-step. Before we jump into the steps, you must have an external Ceph cluster. We assume you have a Ceph storage cluster deployed with Ceph Deploy or manually. Step 1: Deployment of Cephfs Provisioner on Kubernetes Deployment of Cephfs Provisioner on Kubernetes is a straightforward process. Simply log into your Kubernetes cluster and make a manifest file to deploy the RBD provisioner. It is an external dynamic provisioner that is compatible with Kubernetes 1.5+. vim cephfs-provisioner.yml Include the following content within the file. Remember, our deployment relies on RBAC (Role-Based Access Control). Therefore, we will establish the cluster role and bindings before making the service account and deploying the Cephs provisioner. — kind: Namespace apiVersion: v1 metadata: name: cephfs — kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1 metadata: name: cephfs-provisioner namespace: cephfs rules: – apiGroups: [""] resources: ["persistentvolumes"] verbs: ["get", "list", "watch", "create", "delete"] – apiGroups: [""] resources: ["persistentvolumeclaims"] verbs: ["get", "list", "watch", "update"] – apiGroups: ["storage.k8s.io"] resources: ["storageclasses"] verbs: ["get", "list", "watch"] – apiGroups: [""] resources: ["events"] verbs: ["create", "update", "patch"] – apiGroups: [""] resources: ["services"] resourceNames: ["kube-dns","coredns"] verbs: ["list", "get"] — kind: ClusterRoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: cephfs-provisioner namespace: cephfs subjects: – kind: ServiceAccount name: cephfs-provisioner namespace: cephfs roleRef: kind: ClusterRole name: cephfs-provisioner apiGroup: rbac.authorization.k8s.io — apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: cephfs-provisioner namespace: cephfs rules: – apiGroups: [""] resources: ["secrets"] verbs: ["create", "get", "delete"] – apiGroups: [""] resources: ["endpoints"] verbs: ["get", "list", "watch", "create", "update", "patch"] — apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: cephfs-provisioner namespace: cephfs roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: cephfs-provisioner subjects: – kind: ServiceAccount name: cephfs-provisioner — apiVersion: v1 kind: ServiceAccount metadata: name: cephfs-provisioner namespace: cephfs — apiVersion: apps/v1 kind: Deployment metadata: name: cephfs-provisioner namespace: cephfs spec: replicas: 1 selector: matchLabels: app: cephfs-provisioner strategy: type: Recreate template: metadata: labels: app: cephfs-provisioner spec: containers: – name: cephfs-provisioner image: "quay.io/external_storage/cephfs-provisioner:latest" env: – name: PROVISIONER_NAME value: ceph.com/cephfs – name: PROVISIONER_SECRET_NAMESPACE value: cephfs command: – "/usr/local/bin/cephfs-provisioner" args: – "-id=cephfs-provisioner-1" serviceAccount: cephfs-provisioner Next, apply the manifest. $ kubectl apply -f cephfs-provisioner.yml namespace/cephfs created clusterrole.rbac.authorization.k8s.io/cephfs-provisioner created clusterrolebinding.rbac.authorization.k8s.io/cephfs-provisioner created role.rbac.authorization.k8s.io/cephfs-provisioner created rolebinding.rbac.authorization.k8s.io/cephfs-provisioner created serviceaccount/cephfs-provisioner created deployment.apps/cephfs-provisioner created Make sure that the Cephfs volume provisioner pod is in the operational state. $ kubectl get pods -l app=cephfs-provisioner -n cephfs NAME READY STATUS RESTARTS AGE cephfs-provisioner-7b77478cb8-7nnxs 1/1 Running 0 84s Step 2: Obtain the Ceph Admin Key and Create a Secret on Kubernetes Access your Ceph cluster and retrieve the admin key to be used by the RBD provisioner. sudo ceph auth get-key client.admin Save the value of the admin user key displayed by the above command. Later, we will incorporate this key as a secret in Kubernetes. kubectl create secret generic ceph-admin-secret \ –from-literal=key='<key-value>' \ –namespace=cephfs Where <key-value> is your Ceph admin key. Verify the creation by using the following command. $ kubectl get secrets ceph-admin-secret -n cephfs NAME TYPE DATA AGE ceph-admin-secret Opaque 1 6s Step 3: Make Ceph Pools for Kubernetes and Client Key To run a Ceph file system, you will need at least two RADOS pools, one for data and another for metadata. Usually, the metadata pool contains only a few gigabytes of data. Generally, individuals use 64 or 128 for large clusters. Therefore, we recommend a small PG count. Now let us make Ceph OSD pools for Kubernetes: sudo ceph osd pool create cephfs_data 128 128 sudo ceph osd pool create cephfs_metadata 64 64 Create a Ceph file system on the pools. sudo ceph fs new cephfs cephfs_metadata cephfs_data Confirm Ceph File System Creation. $ sudo ceph fs ls name: cephfs, metadata pool: cephfs_metadata, data pools: [cephfs_data ] UI Dashboard Confirmation Step 4: Make Cephfs Storage Class on Kubernetes A StorageClass serves as a means to define the “classes” of storage you offer in Kubernetes. Let’s create a storage class known as “Cephrfs.” vim cephfs-sc.yml Add the following content to the file: — kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: cephfs namespace: cephfs provisioner: ceph.com/cephfs parameters: monitors: 10.10.10.11:6789,10.10.10.12:6789,10.10.10.13:6789 adminId: admin adminSecretName: ceph-admin-secret adminSecretNamespace: cephfs claimRoot: /pvc-volumes Where: ⦁ Cephfs is the name of the StorageClass to be created. ⦁ 10.10.10.11, 10.10.10.12 & 10.10.10.13 are the IP addresses of Ceph Monitors. You can list them with the command: $ sudo ceph -s cluster: id: 7795990b-7c8c-43f4-b648-d284ef2a0aba health: HEALTH_OK services: mon: 3 daemons, quorum cephmon01,cephmon02,cephmon03 (age 32h) mgr: cephmon01(active, since 30h), standbys: cephmon02 mds: cephfs:1 {0=cephmon01=up:active} 1 up:standby osd: 9 osds: 9 up (since 32h), 9 in (since 32h) rgw: 3 daemons active (cephmon01, cephmon02, cephmon03) data: pools: 8 pools, 618 pgs objects: 250 objects, 76 KiB usage: 9.6 GiB used, 2.6 TiB / 2.6 TiB avail pgs: 618 active+clean Once you have updated the file with the accurate value of Ceph monitors, give the Kubectl command to make the StorageClass. $ kubectl apply -f cephfs-sc.yml storageclass.storage.k8s.io/cephfs created Next, list all the available storage classes: $ kubectl get sc NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE ceph-rbd ceph.com/rbd Delete Immediate false 25h cephfs ceph.com/cephfs Delete Immediate false 2m23s Step 5: Do Testing and Create Pod Create a test persistent volume claim to ensure that everything is smooth. $ vim cephfs-claim.yml — kind: PersistentVolumeClaim apiVersion: v1 metadata: name: cephfs-claim1 spec: accessModes: – ReadWriteOnce storageClassName: cephfs resources: requests: storage: 1Gi Apply manifest file $ kubectl apply -f cephfs-claim.yml persistentvolumeclaim/cephfs-claim1 created The successful binding will show the bound status. $ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE ceph-rbd-claim1 Bound pvc-c6f4399d-43cf-4fc1-ba14-cc22f5c85304 1Gi RWO ceph-rbd 25h cephfs-claim1 Bound pvc-1bfa81b6-2c0b-47fa-9656-92dc52f69c52 1Gi RWO cephfs 87s Next, we can launch a test pod using the claim we made. First, create a file to store that data: vim cephfs-test-pod.yaml Add content
How to choose a Freelance Full Stack Web Developer
Hiring a full-stack web developer is a crucial decision for any web development company. The kind of candidate they choose can make or break their project’s aspiration. Full-stack web development requires comprehensive knowledge of developing, testing and deploying web applications. Consequently, you can’t hire any random developer you find on a job portal or the web. Companies that want to recruit a freelance full-stack web developer but don’t know how to get started must read this post. Below, we have accumulated factors to consider when selecting a full-stack web developer. So let’s get started. Step 1: Define Your Project Requirements Clearly Before you begin searching for a full-stack web developer, learn your project requirements. Define the scope of work, the end goal, and the technologies required for the same. It will help you determine the search criteria for a suitable web developer. Step 2: Consider the Skills of the Developer A full-stack web developer is a versatile professional. They must be skilled in both front-end and back-end development. Ensure the developer has the required skill set your project needs. Make a list of programming languages, software, and frameworks needed for the project. On this basis, you can decide the kind of web developer you need. Generally, skills to look for in a full-stack web developer include: Front-end development: Expertise in HTML, CSS, and JavaScript. Furthermore, the developer must have experience in front-end libraries and frameworks. Back-end Development: Knowledge of programming languages, including Node.js and Python is crucial. It will be advantageous if the developer is familiar with back-end frameworks such as Flask or Express. Database Management: Knowledge of different kinds of databases, both SQL and NoSQL, is also essential. Step 3: Check Portfolio Don’t forget to check the portfolio and experience of your potential web developer. A strong portfolio validates the skills and capability of a developer to work on real-world projects. You can visit their websites to learn about past clients and projects they completed. Though certifications alone do not confirm expertise, you can check relevant certifications to validate the developer’s skills. Step 4: Geographical Location of Freelancer The accessibility of the internet has removed all the limits of geographical boundaries. In this digital era, you do not need to confine yourself to locally available talents. You can hire developers from all over the globe. Make sure the freelancer can work in the time zone you prefer. Step 5: Set a Clear Budget and Timeline Before you finalize a full-stack developer and sign a contract, set a clear budget and timeline for the project. It will help you manage the overall cost and period of your project. The cost of hiring a full-stack developer depends on the experience and timeline of the project. Some freelancers charge on an hourly basis, while others have a set fee. Discuss the budget with your freelancer by describing your project requirements. Also, ask them about the expected timeline for the project. You can break down the timeline for your project into different stages. It will help you manage your time effectively. Step 6: Communication Skills You cannot deny the importance of effective communication in web development. Go for a full-stack developer having strong communication skills. A developer has to work with a website designer, other developers, and project managers. An effective communication ensures a smooth workflow. Developers with good communication skills can efficiently convey ideas, address concerns, and update managers about the work progress. Step 7: Team Collaboration The developer you choose must have the ability to work well with others. In a modern web development environment, developers, designers, and testers work together symphonically. Step 8: Conduct Interviews Once you have shortlisted some possible full-stack developers, conduct interviews to choose the most suitable one. An interview will help you get more insight into whether or not a candidate is proficient in meeting project requirements. Evaluate the technical expertise, background, and communication skills of candidates carefully. To assess technical knowledge, you can give programming exercises. If you do not have adequate technical experience and do not know how to check the skills of a full-stack web developer, give preference to a senior full-stack web developer with a lot of experience. Step 9: Make Clear Contracts Make sure billing contracts are clear to you and your freelancers. The contract clearly defines the responsibility of a freelancer and payment terms. The payment terms must include the details of the wage structure, rate, payment schedule and more. These are a few things to consider when hiring a full-stack web developer. Let us learn whether a freelancer or company is a good choice for you. Full-Stack Web Developer: Freelancer vs. Company (Quick Comparison) Whether to choose a freelancer or a company depends on your project requirements, budget and preferences. When you work with a freelancer, you get the following benefits: Affordability Most freelancers charge a lower fee than an established web development company. If you have a limited budget, choosing a freelancer is a good decision. Flexible You have the flexibility to hire freelancers for short-term, long term or just for a specific task. Personalized Attention Since you will work directly with the developer, it will form a close working relationship. Therefore, the freelancer gives personalized attention to your project. The advantages of working with a web development company are below: More Resources Companies have more tools and technologies to manage your projects comparatively. An agency can employ dedicated managers on your project. Scalability As your project grows, you will need more resources to expand your services. Companies can better handle scalability. Delivery Time With most companies, you can expect quick delivery of your project. Conclusion If you are a small company, hiring a freelance web developer is beneficial for you. They are not just affordable but also flexible. On the other hand, if you are a big company with unlimited tasks and a substantial budget, choose a web development company.
