@Scott, I found the dependency error was caused by a workaround of us, it might not the root cause of failure on Ubuntu18.04.1 and Ubuntu18.10
After remove the workaround, I got the cloud-init logs again, please check the new attachment cloud-init-18.04.1-FAIL.tar.gz, there are some Tracebacks in it.
@Scott, I found the dependency error was caused by a workaround of us, it might not the root cause of failure on Ubuntu18.04.1 and Ubuntu18.10
After remove the workaround, I got the cloud-init logs again, please check the new attachment cloud-init- 18.04.1- FAIL.tar. gz, there are some Tracebacks in it.