backport some system unit & cloud-init config changes from devel:

* Simplify how the subiquity client is run on the serial console in the live
  server environment, breaking a unit cycle that sometimes prevents
  subiquity from starting up at all. (LP: #1888497)
* Do not set the password for the installer user via cloud-init as subiquity
  can now do this itself. (LP: #1933523)

debian/changelog

@@ -1,3 +1,13 @@
+livecd-rootfs (2.664.25) UNRELEASED; urgency=medium
+
+  * Simplify how the subiquity client is run on the serial console in the live
+    server environment, breaking a unit cycle that sometimes prevents
+    subiquity from starting up at all. (LP: #1888497)
+  * Do not set the password for the installer user via cloud-init as subiquity
+    can now do this itself. (LP: #1933523)
+
+ -- Michael Hudson-Doyle <michael.hudson@ubuntu.com>  Fri, 23 Jul 2021 11:57:01 +1200
+
 livecd-rootfs (2.664.24) focal; urgency=medium
 
   * Backport generalising of the riscv64 images from hirsute to support

live-build/ubuntu-server/includes.binary/overlay/etc/cloud/cloud.cfg

@@ -17,8 +17,6 @@ preserve_hostname: true
 ssh_pwauth: yes
 chpasswd:
     expire: false
-    list:
-        - installer:RANDOM
 
 # This is the initial network config.
 # It can be overwritten by cloud-init or subiquity.
@@ -34,7 +32,7 @@ network:
                 name: "eth*"
             dhcp4: true
 
-final_message: "## template: jinja\nCloud-init v. {{version}} finished at {{timestamp}}. Datasource {{datasource}}.  Up {{uptime}} seconds\n\n\nWelcome to Ubuntu Server Installer!\n\nAbove you will find SSH host keys and a random password set for the `installer` user. You can use these credentials to ssh-in and complete the installation. If you provided SSH keys in the cloud-init datasource, they were also provisioned to the installer user.\n\nIf you have access to the graphical console, like TTY1 or HMC ASCII terminal you can complete the installation there too."
+# We used to have a custom final_message here.  Just use the default instead.
 
 # Example datasource config
 # datasource:

live-build/ubuntu-server/includes.binary/overlay/usr/lib/systemd/system/getty@tty1.service

@@ -0,0 +1 @@
+/dev/null

live-build/ubuntu-server/includes.binary/overlay/usr/lib/systemd/system/serial-getty@.service.d/subiquity-serial.conf

@@ -1,2 +1,9 @@
+[Unit]
+Description=Subiquity, the installer for Ubuntu Server %I
+After=snapd.seeded.service
+StartLimitInterval=0
+
 [Service]
-ExecStartPre=/bin/systemctl start serial-subiquity@%i.service
+Environment=SNAP_REEXEC=0
+ExecStart=
+ExecStart=/usr/bin/snap run subiquity.subiquity-service %I

live-build/ubuntu-server/includes.binary/overlay/usr/lib/systemd/system/serial-getty@sclp_line0.service.d/subiquity-serial.conf

@@ -1,6 +1,4 @@
-[Unit]
-After=cloud-final.service snapd.seeded.service
 [Service]
 StandardOutput=tty
-ExecStartPre=
+ExecStart=
-ExecStartPre=/usr/bin/snap run subiquity --ssh
+ExecStart=/usr/bin/snap run subiquity --ssh

live-build/ubuntu-server/includes.binary/overlay/usr/lib/systemd/system/snap.subiquity.subiquity-service.service.d/subiquity.conf

@@ -1,7 +1,6 @@
 [Unit]
 IgnoreOnIsolate=yes
 After=systemd-user-sessions.service plymouth-quit-wait.service snap.seeded.service
-ConditionPathExists=!/run/subiquity/complete
 
 [Service]
 Environment=SNAP_REEXEC=0