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.
What this hour is for
How to Install a Let's Encrypt SSL Certificate on openSUSE / SLES installs one thing on a lab openSUSE / SLES host you administer. A certificate here is for one DNS name you control. example.com is documentation.
openSUSE or SLES. zypper is the package tool. dnf and apt are the wrong commands. Use zypper. AppArmor is the usual confinement tool. Do not disable it to make a package start. Do not assume SELinux is enforcing unless getenforce on this host says so.
Do not request a certificate for a name you do not hold. The private key stays on the host. Remove a DNS challenge record after it is issued. Do not paste the key into the ticket. The certificate names the host in the ticket, and the challenge record is gone.
The generator drafts a script. It does not log in and it does not install the packages. 192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the host named in the ticket. Read the draft, then the host, then decide.
Rollback is the file, the package version, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Write the hostname and confirm you administer it.
- Save the current file, package list, or snapshot before any draft is applied.
- Generate the draft and delete every line this ticket did not name.
- Remove documentation addresses, example.com, and any secret.
- Apply one change only when the lab window is open and a console or a second session exists.
- Read the result back and compare it with the ticket.
- Stop. The next change is a different page.
Mistakes that outlive the command
a Let's Encrypt SSL Certificate on openSUSE / SLES goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Pasting a draft you did not read.
- The wrong hostname.
- A secret in the ticket or in git.
- Two changes in one window.
- No copy saved before the change.
- A documentation address left on a host that is leaving the lab.
- Disabling a firewall, AppArmor, or SELinux to make a check pass.
- Calling the generator output a finished production change.
- Do not request a certificate for a name you do not hold. The private key stays on the host. Remove a DNS challenge record after it is issued. Do not paste the key into the ticket.
- A downloaded script piped to a shell.
Decisions to write down
One decision for a Let's Encrypt SSL Certificate on openSUSE / SLES: The hostname matches. The install is only a Let's Encrypt SSL Certificate. The packages come from zypper or a source you already named. No secret is in the script. And the proof is: The certificate names the host in the ticket, and the challenge record is gone.
Checks before you call it done
Confirm this before you call the change done: The hostname matches. The draft was read. No secret is in the note. A firewall or confinement tool was not disabled. The version or the page you expected is written down. And the next install is not started. If one of those fails, stop.
# Install a Let's Encrypt SSL Certificate on openSUSE / SLES.
# zypper only.
# Do not pipe a download to a shell.
# prompt-for-this is not a password.
# 192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.Before you leave the host
How to Install a Let's Encrypt SSL Certificate on openSUSE / SLES ends when the hostname in the prompt matches the hostname in the ticket. If it does not, you are on the wrong host. Stop. A command that succeeded on the wrong host is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the host and does not know which disk is empty. You delete a line that names a host, a path, or an account you did not write down.
192.0.2.10/24, gateway 192.0.2.1, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a host because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save in the ticket or in git. The real secret stays in the password store.
One change is the window. If two things move and the result is wrong, you will not know which one did it. The next change waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied change produces a host nobody can rebuild. Restore the copy you took first.
A second person reads the hostname and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the host alone.
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