disable puppet during major upgrades

tsa/howto/upgrades/buster.mdwn

@@ -40,6 +40,7 @@ process.
 
  4. Perform any pending upgrade and clear out old pins:
 
+        puppet agent --disable "running major upgrade" &&
         : Check for pinned, on hold, packages, and possibly disable &&
         rm -f /etc/apt/preferences /etc/apt/preferences.d/* &&
         rm -f /etc/apt/sources.list.d/testing.list &&
@@ -78,6 +79,7 @@ process.
         apt purge $(for i in apt-transport-https dh-python emacs24-nox gnupg-agent libbind9-140 libcryptsetup4 libdns-export162 libdns162 libevent-2.0-5 libevtlog0 libgdbm3 libicu57 libisc-export160 libisc160 libisccc140 libisccfg140 liblvm2app2.2 liblvm2cmd2.02 liblwres141 libmpfr4 libncurses5 libperl5.24 libprocps6 libpython3.5 libpython3.5-minimal libpython3.5-stdlib libruby2.3 libssl1.0.2 libunbound2 libunistring0 python3-distutils python3-lib2to3 python3.5 python3.5-minimal ruby-nokogiri ruby-pkg-config ruby-rgen ruby-safe-yaml ruby2.3 sgml-base xml-core git-core gcc-6-base:amd64 nagios-plugins-basic perl-modules-5.24 libsensors4:amd64 grub2 iproute libncursesw5 libustr-1.0-1; do dpkg -l "$i" 2>/dev/null | grep -q '^ii' && echo "$i"; done) &&
         dpkg --purge libsensors4:amd64 syslog-ng-mod-json
 
+        puppet agent --enable &&
         (puppet agent -t || true) &&
         (puppet agent -t || true)