Rocky Linux Server Administration Guide

This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.

Where Rocky Linux sits

Rocky Linux aims to be a rebuild of RHEL. The commands feel like the RHEL page: dnf, NetworkManager, firewalld, SELinux enforcing, systemd. The update source is Rocky's, not a Red Hat subscription. Saying RHEL in the inventory is wrong even when the software looks the same.

It is not CentOS Stream, which moves ahead of RHEL, and it is not AlmaLinux, which is a different rebuild project. Pick the project your organisation mirrors and stay on it. Mixing repositories from the siblings is how a later update becomes unreviewable.

The lab address, the named admin, and the key are the same shape as the provisioning guide. 192.0.2.10/24 is documentation only. hostname edge-01 is the lab name.

Migrate onto Rocky as its own project, from the migration guide, not as a side effect of a patch window. A converted host still needs a reboot plan and a rollback image.

The first hour on a lab host

Step 1 on Rocky Linux covers identity. Read os-release and confirm it says Rocky. A mirror or a migration can leave a host that is not what you think. The check is: The inventory says Rocky and the major version. If that check fails, stop and fix the ticket before the next step. The way back is the previous file or the previous image, which the provisioning guide told you to keep. Do not install a second package to hide a failed step. The browser generators for Rocky Linux draft a starter. They do not log in. Read the draft, delete what this lab does not need, and replace prompt-for-this. A line that worked on a different distribution is not a reason to paste it here.

Step 2 on Rocky Linux covers admin. Named user, key, sudo. No root SSH. Same order as the hardening guide. The check is: Key login works. If that check fails, stop and fix the ticket before the next step. The way back is the previous file or the previous image, which the provisioning guide told you to keep. Do not install a second package to hide a failed step. The browser generators for Rocky Linux draft a starter. They do not log in. Read the draft, delete what this lab does not need, and replace prompt-for-this. A line that worked on a different distribution is not a reason to paste it here.

Step 3 on Rocky Linux covers network and firewall. nmcli for the lab address. firewalld allows SSH from the lab prefix only. A copied RHEL subscription setup is not the network config. The check is: The address matches and an outside prefix cannot SSH. If that check fails, stop and fix the ticket before the next step. The way back is the previous file or the previous image, which the provisioning guide told you to keep. Do not install a second package to hide a failed step. The browser generators for Rocky Linux draft a starter. They do not log in. Read the draft, delete what this lab does not need, and replace prompt-for-this. A line that worked on a different distribution is not a reason to paste it here.

Step 4 on Rocky Linux covers SELinux. Leave Enforcing. Investigate denials. A rebuild does not get a weaker default because it was free to install. The check is: getenforce is Enforcing. If that check fails, stop and fix the ticket before the next step. The way back is the previous file or the previous image, which the provisioning guide told you to keep. Do not install a second package to hide a failed step. The browser generators for Rocky Linux draft a starter. They do not log in. Read the draft, delete what this lab does not need, and replace prompt-for-this. A line that worked on a different distribution is not a reason to paste it here.

Step 5 on Rocky Linux covers updates. dnf update from Rocky mirrors only. An Alma or Stream repo line is a different distribution. The check is: The repo list contains Rocky and not a sibling. If that check fails, stop and fix the ticket before the next step. The way back is the previous file or the previous image, which the provisioning guide told you to keep. Do not install a second package to hide a failed step. The browser generators for Rocky Linux draft a starter. They do not log in. Read the draft, delete what this lab does not need, and replace prompt-for-this. A line that worked on a different distribution is not a reason to paste it here.

# Rocky Linux lab. Review before you paste.
# dnf and Rocky repositories, not a Red Hat entitlement.
# firewalld and SELinux Enforcing.
# Lab address 192.0.2.10/24 via 192.0.2.1.
# prompt-for-this is not a password to keep.

The commands you will actually repeat

dnf update from Rocky repositories, read the list, reboot for kernel changes, and record the version. The patch guide's canary still applies.

firewall-cmd and SELinux behave as on the RHEL page. Enforcing stays. The management prefix is allowed. The world is not.

If a package is missing, confirm it is supposed to exist on this major version before you add a third-party repository.

Keep the major version in the ticket. A Rocky 8 habit is not automatically a Rocky 9 file path.

What Rocky Linux is not

Rocky is not a Red Hat support contract. Do not open a vendor case that expects one.

It is not CentOS Linux from years ago, and it is not Stream.

It is not a reason to disable SELinux because a RHEL document and a Rocky host disagreed for an hour.

The hour you stop

Write the hostname, the role, and the clock time before you change Rocky Linux. If this host is also serving users, it is not the lab and this first hour belongs on a spare. The provisioning guide is how the spare gets built. A change without a spare is a change you can still postpone.

Keep the console or the out-of-band path open for the whole hour. Reloading a network service, a firewall, or a secure-shell daemon from the only session is how a lab becomes a drive across town. The hardware guide names that path for a physical machine. A virtual machine uses the hypervisor console. A cloud instance uses the serial console the platform gives you. Test it before the reload, not after.

The address 192.0.2.10/24 and the gateway 192.0.2.1 are documentation. They belong in the lab note and nowhere else. On a real network, use the prefix the network desk already assigned. On a cloud instance, use the address the platform assigned and do not hard-code the documentation range into user-data. If a generator filled the documentation address into a production draft, delete it.

prompt-for-this is a reminder that a secret is missing. It is not a password you set, not a token you commit, and not a string you leave in a configuration file because the service started. The real secret lives in the password store. The ticket says who can read it. A file that still contains the reminder is a file you have not finished.

One service is enough for the first hour on Rocky Linux. The purpose from the fundamentals page says which service. Every other package stays uninstalled until its own guide has a ticket. A host that enables a web server, a database, and a queue in the first hour has three changes and no proof. Finish the login, the address, and the update. Then stop.

Read the package transaction before you accept it. A count of packages is not a review. If the list contains a repository you did not add, stop. If it contains a kernel, the patch guide's reboot decision applies and the console stays open. If it contains software this role does not need, remove that line from the plan rather than installing it and disabling it later.

The previous image, the previous configuration file, or the previous package version is the rollback. Write the path down while the host still works. A rollback you invent after a failed reload is a guess. The migration guide assumes the old copy is still there. Do not delete it in the same hour to free a disk.

When the checks pass, copy the notes into the ticket and leave the host alone. The next host waits until a second person can repeat the login and the address from the notes. A fleet built from memory drifts. A fleet built from the file the provisioning guide stored stays boring, which is the point of Rocky Linux in production.

If a step on Rocky Linux fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied config produces a host nobody can rebuild. Rebuild from the image instead. The time you lose is smaller than the time you will spend explaining the hybrid.

Hand the finished lab to the guide that matches the role: web, mail, storage, backup, or hardening. Rocky Linux being installed is not the same as the role being ready. The role guide has its own proof. Do not skip it because the package manager exited without an error.

A second person reads the hostname, the address, and the rollback path aloud before you build the next host. If they cannot find those three in the ticket, the notes are not done. Silence is not agreement. The check is the sentence they repeat back.

Store the working notes next to the image version. A month from now Rocky Linux will still boot from that pair, and the chat where you remembered a flag will be gone. The file is the memory. The host is replaceable. That is the whole point of writing this hour down.

Rocky Linux checks before a second host

Confirm this before you call the change done: Rocky Linux is the OS the hostname reports, not a neighbour you copied from. The lab address 192.0.2.10/24 is gone before this host is placed on a real network. prompt-for-this is not the password that was set, and no password is in the ticket. The named admin can log in with a key. The package manager used is the one this page names. A network file from a different distribution was not pasted in. The config test or the apply command for this network tool succeeded. The previous image or install file is kept. No new third-party repository was added in the first hour. A service you do not need was not enabled to see what it does. Console or out-of-band access works before you reload SSH. A second person read the hostname and the address. os-release says Rocky Linux. No Alma, Stream, or Red Hat CDN repo was added as a shortcut. SELinux is Enforcing. And the major version is written next to the hostname. If one of those fails, stop.

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