dotnet-sdk-2.1 fails to install on Ubuntu Server 18.04.1

Steps to reproduce

Follow instructions at https://www.microsoft.com/net/download/linux-package-manager/ubuntu18-04/sdk-2.1.401:

$ wget -q https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb

$ sudo dpkg -i packages-microsoft-prod.deb
Selecting previously unselected package packages-microsoft-prod.
(Reading database ... 102222 files and directories currently installed.)
Preparing to unpack packages-microsoft-prod.deb ...
Unpacking packages-microsoft-prod (1.0-ubuntu18.04.1) ...
Setting up packages-microsoft-prod (1.0-ubuntu18.04.1) ...

$ sudo apt-get install apt-transport-https
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'apt' instead of 'apt-transport-https'
apt is already the newest version (1.6.3ubuntu0.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

$ sudo apt-get update
Get:1 https://packages.microsoft.com/ubuntu/18.04/prod bionic InRelease [2,846 B]
Get:2 https://packages.microsoft.com/ubuntu/18.04/prod bionic/main amd64 Packages [21.0 kB]
Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease
Hit:4 http://archive.ubuntu.com/ubuntu bionic-security InRelease
Hit:5 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Fetched 23.8 kB in 1s (35.2 kB/s)
Reading package lists... Done

$ sudo apt-get install dotnet-sdk-2.1
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 dotnet-sdk-2.1 : Depends: dotnet-runtime-2.1 (>= 2.1.3) but it is not going to be installed
                  Depends: aspnetcore-runtime-2.1 (>= 2.1.3) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

CC: @leecow

[jameschch]

Had the same problem on Ubuntu 16.04 and I guess the solution is similar regardless:

sudo apt-get remove libicu57
wget http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu55_55.1-7ubuntu0.4_amd64.deb
sudo dpkg -i libicu55_55.1-7ubuntu0.4_amd64.deb
wget http://security.ubuntu.com/ubuntu/pool/main/o/openssl/libssl1.0.0_1.0.2g-1ubuntu4.15_amd64.deb
sudo dpkg -i libssl1.0.0_1.0.2g-1ubuntu4.15_amd64.deb
sudo apt-get install dotnet-sdk-2.2

[mikeharder]

This appears to be a dup of https://github.com/dotnet/core/issues/1822 (also https://github.com/dotnet/core-setup/issues/4417). The workaround suggested in those issues works for me as well:

sudo add-apt-repository universe