4 Systems & infrastructure

16 entries match these filters

• 0104 Build a Proxmox VE cluster with pvecm and live-migrate VMs Join Proxmox VE nodes into a cluster with pvecm create and pvecm add, check quorum with pvecm status, then move running VMs… Advanced · How-to · Linux Article Clusters & high availability · VMs & containers 15 Oct 2026
• 0105 High availability in Proxmox VE: HA resources, fencing and affinity rules Proxmox VE HA restarts VMs and containers on another node when a node fails. Learn the requirements, how watchdog fencing protects your… Advanced · Concept · Linux Article Clusters & high availability 15 Oct 2026
• 0112 Fix: TASK ERROR: cluster not ready – no quorum? The node is not part of a quorate cluster, so /etc/pve is read-only and guests cannot be started or changed. Restore the… Advanced · Fix · Linux Article Clusters & high availability 15 Oct 2026
• 0122 PCA 3.x health monitoring and upgrade workflow overview How Private Cloud Appliance 3.x reports health (Grafana, Prometheus, Loki, platform health checks) and how appliance upgrades work: ISO images, an upgrade… Advanced · Concept · Linux Article Administration & monitoring 15 Oct 2026
• 0126 KVM snapshots and cloning with virsh and virt-clone Take, list, revert and delete libvirt snapshots with virsh, understand internal vs external and disk-only snapshots, and clone a stopped VM with… Advanced · How-to · Linux Article Basics 15 Oct 2026
• 0138 Kubernetes RBAC basics: least-privilege access for a service account RBAC controls who may do what in a cluster with Roles, ClusterRoles and bindings. This guide grants a CI service account deploy… Advanced · How-to · Linux Article Concepts · Config, secrets & storage 15 Oct 2026
• 0144 Fix: Pod stuck in Pending with “0/3 nodes are available: Insufficient cpu” The scheduler cannot find a node with enough unreserved CPU for the pod's request. Compare the request with node allocatable resources, then… Advanced · Fix · Linux Article Troubleshooting · Workloads & services 15 Oct 2026
• 0145 Fix: OOMKilled (exit code 137) in Kubernetes A container used more memory than its limit and the kernel killed it. Confirm the reason, measure real usage, then raise the… Advanced · Fix · Linux Article Troubleshooting · Workloads & services 15 Oct 2026
• 0155 Security Context Constraints (SCC) and why root containers fail on OpenShift SCCs decide which user ID, capabilities and volumes a pod may use. Learn how restricted-v2 assigns random UIDs, how to see which… Advanced · Concept · Linux Article Cluster administration · Concepts 15 Oct 2026
• 0159 OpenShift cluster health snapshot: oc adm, nodes, MachineConfigPools and updates An admin overview of OpenShift day-2 checks (cluster version, update channels, cluster Operators, nodes, MachineConfigPools, must-gather) with a read-only bash script that… Advanced · Reference · Linux, macOS Script Cluster administration · Troubleshooting 15 Oct 2026
• 0160 Fix: Permission denied in a container on OpenShift because of the random UID A container that works under Docker or Kubernetes crashes on OpenShift with permission denied, because restricted-v2 runs it with a random non-root… Advanced · Fix · Linux Article Troubleshooting 15 Oct 2026
• 0171 Extend an LVM logical volume and filesystem online (safe script) A bash script that grows the LVM volume behind a mount point, checks the filesystem type and free space first, and runs… Advanced · How-to · Linux Script Disks, LVM & filesystems 15 Oct 2026
• 0178 Create a sudo user with an SSH key and disable password login A bash script that creates an admin user in the sudo or wheel group, installs their SSH public key and can switch… Advanced · How-to · Linux Script Keys & config · Users, sudo & hardening 15 Oct 2026
• 0184 Ansible Vault: keep passwords and keys encrypted in your repo Ansible Vault encrypts variable files or single values so secrets can live in Git next to your playbooks. Create, edit and rekey… Advanced · How-to · Linux, macOS Article Ansible 15 Oct 2026
• 0189 Terraform remote state: backends, locking and migrating local state Move Terraform state from a local file into a shared backend such as S3 with locking, so a team can work safely.… Advanced · How-to · Any system Article Terraform 15 Oct 2026
• 0190 Fix: Terraform Error acquiring the state lock Another run holds the lock on your Terraform state, or a crashed run left it behind. Find out who holds it, wait… Advanced · Fix · Any system Article Terraform 15 Oct 2026