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HW2: move interlude to a separate file
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,170 @@ | ||
| ## Interlude 1: Beating Ansible Installation into Shape | ||
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| As noted in [homework 1](../hw1-the_lab/) I decided to install Ansible | ||
| into a Python Virtual Environment (venv). That seemd to work fine, until | ||
| I tried to use the `ios_commands` module. While the `raw` module, using | ||
| [OpenSSH](https://www.openssh.com/), worked fine, the `ios_command` | ||
| module, using [Paramiko](http://www.paramiko.org/), did not: | ||
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| ``` | ||
| fatal: [P1-oob.lab.local]: FAILED! => {"changed": false, "msg": "unable to open shell. Please see: https://docs.ansible.com/ansible/network_debug_troubleshooting.html#unable-to-open-shell"} | ||
| ``` | ||
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| The link provided in the error message hinted at authentication errors | ||
| as the most likely cause, but it also provided information on how gather | ||
| debugging information: This is done by defining two environment variables, | ||
| `ANSIBLE_LOG_PATH` and `ANSIBLE_DEBUG`, to useful values and adding | ||
| `-vvvv` to the Ansible invocation: | ||
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| ``` | ||
| env ANSIBLE_LOG_PATH=debug.log ANSIBLE_DEBUG=True ansible-playbook -l P1-oob.lab.local -vvvvv playbooks/topology.yml | ||
| ``` | ||
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| In my case the file `debug.log` told me that Paramiko was not installed: | ||
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| ``` | ||
| AnsibleError: paramiko is not installed | ||
| ``` | ||
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| Taking a look at the contents of the Python Virtual Environment showed | ||
| Paramiko, trying to install or upgrade it did not change anything: | ||
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| ``` | ||
| (ansible)$ pip install paramiko | ||
| Requirement already satisfied (use --upgrade to upgrade): paramiko in /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages | ||
| Cleaning up... | ||
| (ansible)$ pip install paramiko --upgrade | ||
| Requirement already up-to-date: paramiko in /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages | ||
| Cleaning up... | ||
| ``` | ||
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| Manually importing Paramiko in a Python interpreter showed that a | ||
| dependency of Paramiko was not installed: | ||
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| ``` | ||
| (ansible)$ python | ||
| Python 2.7.6 (default, Nov 23 2017, 15:49:48) | ||
| [GCC 4.8.4] on linux2 | ||
| Type "help", "copyright", "credits" or "license" for more information. | ||
| >>> import paramiko | ||
| File "<stdin>", line 1, in <module> | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/paramiko/__init__.py", line 22, in <module> | ||
| from paramiko.transport import SecurityOptions, Transport | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/paramiko/transport.py", line 34, in <module> | ||
| from cryptography.hazmat.primitives.ciphers import algorithms, Cipher, modes | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/hazmat/primitives/ciphers/__init__.py", line 7, in <module> | ||
| from cryptography.hazmat.primitives.ciphers.base import ( | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/hazmat/primitives/ciphers/base.py", line 12, in <module> | ||
| from cryptography.exceptions import ( | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/exceptions.py", line 7, in <module> | ||
| from enum import Enum | ||
| ImportError: No module named enum | ||
| >>> | ||
| ``` | ||
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| I then added the `enum` Python module to the venv using `pip`: | ||
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| ``` | ||
| (ansible)$ pip install enum | ||
| Downloading enum-0.4.6.tar.gz | ||
| Running setup.py (path:/home/auerswald/work/bnas2018/ansible/build/enum/setup.py) egg_info for package enum | ||
| Requirement already satisfied (use --upgrade to upgrade): setuptools in /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages (from enum) | ||
| Installing collected packages: enum | ||
| Running setup.py install for enum | ||
| Could not find .egg-info directory in install record for enum | ||
| Successfully installed enum | ||
| Cleaning up... | ||
| ``` | ||
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| This still did not work, and would come back to bite me later because | ||
| that `enum` package was wrong (I needed `enum34` instead), but running | ||
| the playbook now resulted in a Syslog message on the router: | ||
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| ``` | ||
| *Feb 24 20:35:45.903: %SSH-4-SSH2_UNEXPECTED_MSG: Unexpected message type has arrived. Terminating the connection from 192.168.254.42 | ||
| ``` | ||
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| Thus Ansible could use Paramiko to connect to (network) devices. The file | ||
| `debug.log` showed a new Paramiko error: | ||
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| ``` | ||
| 2018-02-24 21:09:35,709 paramiko.transport from cryptography.x509 import certificate_transparency | ||
| 2018-02-24 21:09:35,709 paramiko.transport ImportError: cannot import name certificate_transparency | ||
| ``` | ||
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| Again the `certificate_transparency.py` file is already available in the venv, | ||
| but manually importing results in an error: | ||
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| ``` | ||
| (ansible)$ python | ||
| Python 2.7.6 (default, Nov 23 2017, 15:49:48) | ||
| [GCC 4.8.4] on linux2 | ||
| Type "help", "copyright", "credits" or "license" for more information. | ||
| >>> from cryptography.x509 import certificate_transparency | ||
| Traceback (most recent call last): | ||
| File "<stdin>", line 1, in <module> | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/x509/__init__.py", line 8, in <module> | ||
| from cryptography.x509.base import ( | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/x509/base.py", line 16, in <module> | ||
| from cryptography.x509.extensions import Extension, ExtensionType | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/x509/extensions.py", line 10, in <module> | ||
| import ipaddress | ||
| ImportError: No module named ipaddress | ||
| >>> | ||
| ``` | ||
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| I then installed the `ipaddress` Python package into the Python Virtual | ||
| Environment: | ||
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| ``` | ||
| (ansible)$ pip install -U ipaddress | ||
| Downloading/unpacking ipaddress | ||
| Downloading ipaddress-1.0.19.tar.gz | ||
| Running setup.py (path:/home/auerswald/work/bnas2018/ansible/build/ipaddress/setup.py) egg_info for package ipaddress | ||
| Installing collected packages: ipaddress | ||
| Running setup.py install for ipaddress | ||
| Could not find .egg-info directory in install record for ipaddress | ||
| Successfully installed ipaddress | ||
| Cleaning up... | ||
| ``` | ||
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| Now I was getting somewhere, because Ansible no longer failed to open | ||
| a shell, but crashed with the error message: | ||
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| ``` | ||
| ERROR! Unexpected Exception, this is probably a bug: 'type' object is not iterable | ||
| [...] | ||
| File "/home/auerswald/work/bnas2018/ansible/local/lib/python2.7/site-packages/cryptography/x509/name.py", line 28, in <module> | ||
| _ASN1_TYPE_TO_ENUM = dict((i.value, i) for i in _ASN1Type) | ||
| TypeError: 'type' object is not iterable | ||
| ``` | ||
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| Trying the respective code by hand in a Python interpreter showed that | ||
| the `enum` package I installed was not compatible with the way the | ||
| `cryptography` package used it. The solution was to ask Google, which | ||
| answered that the Python package to provide an `Enum` similar to that | ||
| introduced with Python 3.4 was called `enum34`. That seemed promising, | ||
| thus I removed `enum` and installed `enum34`: | ||
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| ``` | ||
| (ansible)$ pip uninstall enum | ||
| Uninstalling enum: | ||
| /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages/enum-0.4.6-py2.7.egg-info | ||
| /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages/enum.py | ||
| /home/auerswald/work/bnas2018/ansible/lib/python2.7/site-packages/enum.pyc | ||
| Proceed (y/n)? y | ||
| Successfully uninstalled enum | ||
| (ansible)$ pip install enum34 | ||
| Downloading/unpacking enum34 | ||
| Downloading enum34-1.1.6-py2-none-any.whl | ||
| Installing collected packages: enum34 | ||
| Successfully installed enum34 | ||
| Cleaning up... | ||
| ``` | ||
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| Now the Paramiko connection was setup correctly and the Ansible `ios_command` | ||
| module worked as expected. Back to the regularly scheduled program. ;-) | ||
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| --- | ||
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| [BNAS2018 Homework 2](README.md) | [BNAS2018 GitHub repository](https://github.com/auerswal/bnas2018) | [My GitHub user page](https://github.com/auerswal) | [My home page](https://www.unix-ag.uni-kl.de/~auerswal/) |