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Posted to notifications@libcloud.apache.org by lhuard1A <gi...@git.apache.org> on 2016/03/25 17:32:18 UTC
[GitHub] libcloud pull request: Fix a race condition in GCE’s list_nodes(...
GitHub user lhuard1A opened a pull request:
https://github.com/apache/libcloud/pull/727
Fix a race condition in GCE’s list_nodes()
Invoking GCE’s `list_nodes()` while some VMs are being shutdown can result
in the following exception to be raised out of `list_nodes()`:
```
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 1411, in list_nodes
v.get('instances', [])]
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 5065, in _to_node
extra['boot_disk'] = self.ex_get_volume(bd['name'], bd['zone'])
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 3982, in ex_get_volume
response = self.connection.request(request, method='GET').object
File "/usr/lib/python2.7/site-packages/libcloud/common/google.py", line 684, in request
*args, **kwargs)
File "/usr/lib/python2.7/site-packages/libcloud/common/base.py", line 736, in request
response = responseCls(**kwargs)
File "/usr/lib/python2.7/site-packages/libcloud/common/base.py", line 119, in __init__
self.object = self.parse_body()
File "/usr/lib/python2.7/site-packages/libcloud/common/google.py", line 259, in parse_body
raise ResourceNotFoundError(message, self.status, code)
libcloud.common.google.ResourceNotFoundError: {'domain': 'global', 'message': "The resource 'projects/lenaic/zones/europe-west1-c/disks/devops-reg' was not found", 'reason': 'notFound'}
```
The above error occurred while the `devops-reg` machine was being deleted.
The issue occurs when the following events happen in that order:
* [`list_nodes()` sends a request to list all the instances.](https://github.com/apache/libcloud/blob/trunk/libcloud/compute/drivers/gce.py#L1622)
At this point, the `devops-reg` was still existing.
* The `devops-reg` instance is deleted.
* `list_nodes()` calls `_to_node` which calls [`ex_get_volume` which attempts to retrieve the information of the volumes](https://github.com/apache/libcloud/blob/trunk/libcloud/compute/drivers/gce.py#L4235)
But, as the instance was deleted since it was listed, `ex_get_volume` raises a `ResourceNotFoundError` exception.
When this happens, we should simply discard the node that was deleted during the execution of `list_nodes()` and return the information about the other nodes.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/lhuard1A/libcloud fix_race_in_list_nodes
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/libcloud/pull/727.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #727
----
commit f49cea83cdb0ffe41b667a53a747f598ff90576d
Author: Lénaïc Huard <lh...@amadeus.com>
Date: 2016-03-25T16:00:48Z
Fix a race condition in GCE’s list_nodes()
Invoking GCE’s `list_nodes()` while some VMs are being shutdown can result
in the following exception to be raised out of `list_nodes()`:
```
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 1411, in list_nodes
v.get('instances', [])]
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 5065, in _to_node
extra['boot_disk'] = self.ex_get_volume(bd['name'], bd['zone'])
File "/usr/lib/python2.7/site-packages/libcloud/compute/drivers/gce.py", line 3982, in ex_get_volume
response = self.connection.request(request, method='GET').object
File "/usr/lib/python2.7/site-packages/libcloud/common/google.py", line 684, in request
*args, **kwargs)
File "/usr/lib/python2.7/site-packages/libcloud/common/base.py", line 736, in request
response = responseCls(**kwargs)
File "/usr/lib/python2.7/site-packages/libcloud/common/base.py", line 119, in __init__
self.object = self.parse_body()
File "/usr/lib/python2.7/site-packages/libcloud/common/google.py", line 259, in parse_body
raise ResourceNotFoundError(message, self.status, code)
libcloud.common.google.ResourceNotFoundError: {'domain': 'global', 'message': "The resource 'projects/lenaic/zones/europe-west1-c/disks/devops-reg' was not found", 'reason': 'notFound'}
```
The above error occurred while the `devops-reg` machine was being deleted.
The issue occurs when the following events happen in that order:
* [`list_nodes()` sends a request to list all the instances.](https://github.com/apache/libcloud/blob/trunk/libcloud/compute/drivers/gce.py#L1622)
At this point, the `devops-reg` was still existing.
* The `devops-reg` instance is deleted.
* `list_nodes()` calls `_to_node` which calls [`ex_get_volume` which attempts to retrieve the information of the volumes](https://github.com/apache/libcloud/blob/trunk/libcloud/compute/drivers/gce.py#L4235)
But, as the instance was deleted since it was listed, `ex_get_volume` raises a `ResourceNotFoundError` exception.
When this happens, we should simply discard the node that was deleted during the execution of `list_nodes()` and return the information about the other nodes.
----
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[GitHub] libcloud pull request: Fix a race condition in GCE’s list_nodes(...
Posted by asfgit <gi...@git.apache.org>.
Github user asfgit closed the pull request at:
https://github.com/apache/libcloud/pull/727
---
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