there can be a better way to group than context-describe-context-context .
moreover, since this is ec2 test, the context 'ec2' seems redundant.

suggestion as below can be considered to group the tests:
describe 'knife ec2 integration tests'
describe 'server list'
     it 'displays all options when --help specified'
     it 'does blah blah when option --availibility-zone specified'
     it 'does something else'
describe 'server create'
     it '...'