Deepak Prasad

Learn how Kubernetes labels and selectors work, add and remove labels with kubectl on Pods, nodes, and Deployments, and use matchLabels and matchExpressions in YAML.

Use kubectl api-resources, api-versions, and explain to discover supported resource types, API versions, and valid YAML fields on any Kubernetes cluster.

Install kubectl on Rocky Linux, RHEL, Ubuntu, or Debian, then configure kubeconfig, contexts, and remote access to a Kubernetes cluster.

Learn the Linux boot process from UEFI or BIOS through GRUB, the kernel, initramfs, and systemd, with inspection commands and troubleshooting.

Create coordinated LVM snapshot sets with snapm, boot into a snapshot through Boom and GRUB, inspect an earlier system state, revert failed changes, monitor snapshot capacity, and delete snapshot sets on Rocky Linux …

Convert an existing dhcpd.conf to Kea JSON with KeaMA, correct unsupported directives, test reservations and leases on an isolated lab, compare DHCP offers, and cut over from ISC DHCP to Kea with a tested rollback path.

tmux is a terminal multiplexer that keeps shell sessions running in the background, splits one screen into panes and windows, and reconnects after SSH drops. Default prefix is Ctrl+b.

virt-install provisions KVM guests through libvirt from ISO, install trees, PXE, or existing disk images. Use it to set CPU, memory, disks, networks, and graphics before the guest boots.

Install and configure the Kea DHCPv4 server on Rocky Linux 10, RHEL 10, or AlmaLinux 10 with a JSON address pool, gateway and DNS options, MAC reservation, and lease verification on an isolated lab network.

Reset or change the Directory Manager password in 389 Directory Server with online dsconf over LDAPS, offline pwdhash and dse.ldif editing, verification, rollback, and per-replica rollout.

Troubleshoot slow LDAP searches in 389 Directory Server using client timing, access-log metrics, unindexed-filter notes, indexes, caches, and replica comparison.

Fix missing or stale memberOf in 389 Directory Server by checking group data, plug-in scope, fix-up filters, shared configuration, and replication.

Fix LDAP error 53 in 389 Directory Server by reading the additional info line, then checking password policy, read-only mode, RootDN Access Control, TLS SSF, and access logs.

Fix LDAP error 49 in 389 Directory Server by checking the password, bind DN, account state, access logs, application secrets, and replication credentials.

Understand how 389 Directory Server hashes LDAP passwords, inspect userPassword prefixes, change the global storage scheme, migrate legacy hashes after successful binds, and test application compatibility.

Use dsconf to manage a running 389 Directory Server: backends, indexes, replication, plug-ins, logs, security, schema, monitoring, and online backups.

Install 389 Directory Server, create an LDAP instance with dscreate, configure a directory suffix, verify the service, and test LDAP access.

Use perf stat, perf record, and perf report on Linux to find CPU bottlenecks, collect call graphs, and resolve symbols with debuginfod on Rocky Linux, RHEL, Debian, Ubuntu, and other distributions.

Fix LDAP works but LDAPS fails in 389 Directory Server by checking port 636, the TLS handshake, client CA trust, hostname matching, server certificates, and access logs.

Fix LDAP error 65 in 389 Directory Server by reading the additional info line, then checking object class MUST and MAY rules, entry state, custom schema, plug-ins, and replica schema parity.

Install Apache, MariaDB, PHP, and PHP-FPM on Rocky Linux, RHEL, AlmaLinux, or Oracle Linux, then verify the complete LAMP stack with a PHP database test.

Install PHP 8.4 from native AppStream php8.4-* packages on RHEL 10.2+, Rocky Linux, AlmaLinux, Oracle Linux, or CentOS Stream 10 when dnf info php8.4 confirms availability, then configure php-fpm and verify Apache or …

Replace native PHP 8.3 packages with php8.4-* RPMs on EL 10, back up configuration, check application compatibility, migrate PHP-FPM settings, verify web applications, troubleshoot failures, and roll back if required.

Fix LDAP error 50 in 389 Directory Server by checking ACIs on the target and its parents, group membership, deny rules, Get Effective Rights, and access logs.

Install and configure BIND on RHEL, Rocky Linux, or AlmaLinux with forward and reverse zones, controlled recursion, NetworkManager clients, and dig testing.

Install PostgreSQL 18 on RHEL, Rocky Linux, AlmaLinux, Oracle Linux, or CentOS Stream using native packages or PGDG, then initialize and verify the server.

Configure Apache LDAP authentication with 389 Directory Server using mod_authnz_ldap, StartTLS, group authorization, and troubleshooting.

Store SSH public keys in 389 Directory Server, configure SSSD and OpenSSH key lookup, and test key addition, rotation, and revocation.

Configure Linux LDAP authentication with 389 Directory Server and SSSD on Rocky Linux 10: POSIX users, TLS, authselect, identity lookup, login, and offline caching.

Migrate legacy network-scripts and ifcfg profiles to NetworkManager keyfiles on RHEL, Rocky Linux, AlmaLinux, Oracle Linux, and CentOS Stream before upgrading to a release that no longer reads ifcfg files.