Migrated Cron job to Systemd timer

Author: Nikhil Dikshit

amzn-changelog

@@ -1,3 +1,8 @@
+* Thu Mar 09 2023 Nikhil Dikshit <nikhildi@amazon.com> 2.0-1.amzn2023.0.3
+- Migrated Cron job to Systemd timer
+- Trigger update-motd.service after cloud-final.service
+- Set RemainAfterExit=no on update-motd so that timer can restart it after exit
+
 * Thu Feb 02 2023 Stewart Smith <trawets@amazon.com> - 2.0-1.amzn2023.0.2
 - Mass rebuild for AL2023
 

cron_update-motd

@@ -1,11 +1,15 @@
 [Unit]
 Description=Dynamically Generate Message Of The Day
-After=network-online.target
+# running update-motd.service after cloud-final.service, which will be later in the boot process
+# this is to avoid running update-motd at the same time with other services such as dnf activities in userdata scripts
+After=network-online.target cloud-final.service
 
 [Service]
 Type=oneshot
 ExecStart=/usr/sbin/update-motd
-RemainAfterExit=yes
+# update-motd should not be considered active when its processes have exited
+# timer should be able to restart update-motd even after exit
+RemainAfterExit=no
 
 [Install]
 WantedBy=multi-user.target

update-motd.service

@@ -1,5 +1,5 @@
 %define _trivial	.0
-%define _buildid	.2
+%define _buildid	.3
 Name:       update-motd
 Version:    2.0
 Release:    1%{?dist}%{?_trivial}%{?_buildid}
@@ -13,7 +13,7 @@ BuildRequires: systemd-devel
 %{?systemd_requires}
 
 Source0:    sbin_update-motd
-Source1:    cron_update-motd
+Source1:    update-motd.timer
 Source2:    update-motd.service
 
 %description
@@ -24,7 +24,7 @@ Based on and compatible with the framework implemented Ubuntu.
 rm -rf %{buildroot}
 install -d %{buildroot}/etc/update-motd.d
 install -D -m 0755 %{SOURCE0} %{buildroot}/usr/sbin/update-motd
-install -D -m 0644 %{SOURCE1} %{buildroot}/etc/cron.d/update-motd
+install -D -m 0644 %{SOURCE1} %{buildroot}%{_unitdir}/update-motd.timer
 install -D -m 0644 %{SOURCE2} %{buildroot}%{_unitdir}/update-motd.service
 # for %ghost
 install -d %{buildroot}/var/lib/update-motd
@@ -62,8 +62,7 @@ fi
 %defattr(-,root,root,-)
 %dir /etc/update-motd.d
 %dir /var/lib/update-motd
-%config /etc/cron.d/update-motd
-%config %{_unitdir}/update-motd.service
+%config %{_unitdir}/update-motd.{service,timer}
 /usr/sbin/update-motd
 %ghost /var/lib/update-motd/motd
 

update-motd.spec

@@ -0,0 +1,11 @@
+[Unit]
+Description=Timer for Dynamically Generate Message Of The Day
+
+[Timer]
+OnUnitActiveSec=720min
+RandomizedDelaySec=720min
+FixedRandomDelay=true
+Persistent=true
+
+[Install]
+WantedBy=timers.target