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Setting up SSL certificate

HTTPS workflow 2020

Many documentations outsides, but some of them are out of date, and some of them only applies to already setup servers like Apaches, Nginx, etc. So I have summed up my experience on this.

Install certbot

sudo apt-get update

sudo apt-get install software-properties-common

sudo apt-add-repository ppa:certbot/certbot -y

sudo apt-get update -y

sudo apt-get install certbot -y


There are mainly 2 ways a CA can verify a domain integrity.

  • Through Domain Name TXT record challenge
  • Through HTTP Server challenge

Both of them will have an ACME challenge that a CA will verify against it.

You will have to do this process every 90 days if your certs are from Let's Encrypt or SSL For Free.

Get certificate

sudo certbot certonly --standalone --preferred-challenges http -d -d

standalone means certbot will spin up a temporary web server listening port 80 for HTTP-01 challenge by its python script. So you don't need a webserver running.

You shall obtain certificates at /etc/letsencrypt/live/

Make symlinks

Make symlinks for easy access

sudo ln -s /etc/letsencrypt/live/ /yourprojectfolder/ssl/

Allowing non-root access

sudo chmod 755 -R /etc/letsencrypt/{live,archive}

Archive is included here because certificates in live folder are just symlinks back to archive.

Check if certificate is deployed

Setup hooks to renewal

Often times you want to do preparations before and after setup of SSL certificates, setup hooks will help you do so

sudo sh -c 'printf "#!/bin/sh\nservice haproxy stop\n" > /etc/letsencrypt/renewal-hooks/pre/'
sudo sh -c 'printf "#!/bin/sh\nservice haproxy start\n" > /etc/letsencrypt/renewal-hooks/post/'
sudo chmod 755 /etc/letsencrypt/renewal-hooks/pre/
sudo chmod 755 /etc/letsencrypt/renewal-hooks/post/

One suggestion is to allow access by non-root users

chmod 755 -R /etc/letsencrypt/{live,archive}

Renewal is automatically setup


sudo cat /etc/cron.d/certbot

should contain

# /etc/cron.d/certbot: crontab entries for the certbot package
# Upstream recommends attempting renewal twice a day
# Eventually, this will be an opportunity to validate certificates
# haven't been revoked, etc.  Renewal will only occur if expiration
# is within 30 days.
# Important Note!  This cronjob will NOT be executed if you are
# running systemd as your init system.  If you are running systemd,
# the cronjob.timer function takes precedence over this cronjob.  For
# more details, see the systemd.timer manpage, or use systemctl show
# certbot.timer.

0 */12 * * * root test -x /usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep int(rand(43200))' && certbot -q renew

This job will be executed by the period specified by the cron expression in the file.

As long as the file exist in the cron.d directory, the job will be executed.

Check logs

$ grep CRON /var/log/syslog

Check renewal procedures

sudo certbot renew --dry-run


tar -czvf backup.tar.gz /etc/letsencrypt

Revoke certificate

sudo certbot revoke --cert-path /path/to/cert/server.cert --key-path /path/to/cert/server.key

sudo certbot delete


Debug certification error

Logs are located at


might be quite long, so use tail or vi if possible.

Register wildcards

Registering wildcard domain (e.g. * requires DNS-01 challenge, which requires to change NameServer's record, and cannot be renewed easily. It will require you to update the DNS records if API is available by your NameServer.

sudo certbot -d $DOMAIN -d $WILDCARD --manual --preferred-challenges dns certonly

Manual procedure also doesn't have very much flexibility, only specific kinds of plugins are allowed with manual setup for renewal (Maybe I'm wrong)

Useful links


Other than cron.d, crontab can be setup to perform similar periodic tasks

List crontab

crontab -l

Backup crontab

crontab -l > cron-backup.txt

Remove crontab

crontab -r

Restore crontab

crontab cron-backup.txt

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