 
      sudo do-release-upgrade...
Setting up libnih1:amd64 (1.0.3-6ubuntu2) ...If it freezes here
Open another terminal or something and restart the system.
(Just in case, check top to see if there are any running processes)
$ sudo rebootAfter rebooting,
$ sudo apt updateWhen you try this
Err:1 http://security.ubuntu.com/ubuntu bionic-security InRelease
Temporary failure resolving 'security.ubuntu.com'
Err:2 http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu bionic InRelease
Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
Err:3 http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu bionic-updates InRelease
Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
Err:4 http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu bionic-backports InRelease
Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
Reading package lists... Done
Building dependency tree
Reading state information... Done
257 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: Failed to fetch http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu/dists/bionic/InRelease Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
W: Failed to fetch http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
W: Failed to fetch http://ap-northeast-1.ec2.archive.ubuntu.com/ubuntu/dists/bionic-backports/InRelease Temporary failure resolving 'ap-northeast-1.ec2.archive.ubuntu.com'
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/bionic-security/InRelease Temporary failure resolving 'security.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.Since such an error appeared
sudo dpkg --configure -a
sudo apt --fix-broken install
sudo apt upgrade -yIf errors occur, error handling commands are often displayed, so read them carefully and
sudo apt update -y; sudo apt upgrade -y;Make sure no errors are displayed, and once the errors are gone
sudo rebootPitfall
If you are using venv linked to Python 3.5 -> Python 3.6, it will break. Since it's an opportunity, you should recreate the venv with Python 3.6.
python3.6 -m venv venvWhen installing MySQL 5.7, there might be a conflict, and mysql-server may not be installed.
Errors were encountered while processing: mysql-server-5.7 mysql-server Error in function:
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After the problem report has been sent, please fill out the form in the automatically opened web browser.
What would you like to do? Your options are: S: Send report (389.0 KB) V: View report K: Keep report file for sending later or copying to somewhere else I: Cancel and ignore future crashes of this program version C: Cancel
After cancelling, remove it temporarily
sudo apt remove mysql-serverIt might be easier to reinstall after the upgrade is complete. Be sure to back up the DB just in case.
sudo apt install mysql-server