[george.hartzell@172-16-193-97 spack-explore-docker]$ spack containerize
Running `spack containerize` with the example `spack.yaml` file fails
with an error that ends like so:
```
[...]
File "/local_scratch/hartzell/tmp/spack-explore-docker/lib/spack/external/ruamel/yaml/scanner.py", line 165, in need_more_tokens
self.stale_possible_simple_keys()
File "/local_scratch/hartzell/tmp/spack-explore-docker/lib/spack/external/ruamel/yaml/scanner.py", line 309, in stale_possible_simple_keys
"could not find expected ':'", self.get_mark())
ruamel.yaml.scanner.ScannerError: while scanning a simple key
in "/local_scratch/hartzell/tmp/spack-explore-docker/spack.yaml", line 26, column 1
could not find expected ':'
in "/local_scratch/hartzell/tmp/spack-explore-docker/spack.yaml", line 28, column 5
```
Indenting the block string fixes the problem for me.
CentOS 7,
```
$ spack --version
0.14.2-1529-ec58f28c2
```
e6bb8360d0