Articles tagged sysadmin

  1. Upgrading an Amazon EC2 Instance from Ubuntu Trusty to Xenial

    I had a bad time.
    I ran a do-release-upgrade on one of my Amazon EC2 instances to try and upgrade it from 14.04 (Trusty) to 16.04 (Xenial). After the update and a reboot the box refused to come back up. When I detached the drive and attached it to another to check syslog I found this:

    /sbin/dhclient -1 -v -pf /run/ -lf /var/lib/dhcp/dhclient.eth0.leases -I -df /var/lib/dhcp/dhclient6.eth0.leases eth0
    Usage: dhclient [-4|-6] [-SNTP1dvrx] [-nw] [-p <port>] [-D LL|LLT]
                 [-s server-addr] [-cf config-file] [-lf lease-file]
                 [-pf pid-file] [--no-pid] [-e VAR=val]
                 [-sf script-file] [interface]
    Failed to bring up eth0.

    Oh good, it forgot how to eth0.
    I spent about four hours figuring out how to fix it:

    apt update
    apt -y upgrade
    cat  << EOF > /etc/update-manager/release-upgrades.d/unauth.cfg
    apt install -y network-manager
    apt update
    apt -y upgrade
    systemctl enable systemd-networkd
    systemctl enable systemd-resolved
    dpkg-reconfigure resolvconf
    apt-get -y autoremove
    rm /etc/update-manager/release-upgrades.d/unauth.cfg
    1. Make sure you are up to date first.
    2. Some packages (python3) complain that they are unauthenticated. Feel free to skip this if you want.
    3. Install the network-manager
    4. Leap of faith... do the upgrade
    5. Finish the upgrade by installing the rest of the packages.
    6. Enable the systemd network daemon and resolver daemon
    7. Reconfigure resolvconf so you can dns
    8. Get rid of the unauth.cfg file you created
    9. Reboot and pray.

    Thanks to these three links for the solutions (I just put them together):