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https://issues.apache.org/jira/browse/LIBCLOUD-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13951010#comment-13951010
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Matthew Lehman commented on LIBCLOUD-532:
-----------------------------------------
This is also an issue with Rackspace and appears to happen much more
frequently. Paramiko's exception and the server logs leave you a bit lost here
as well because it just results in :
fatal: No supported key exchange algorithms [preauth]
Received signal 15; terminating.
on the server side and:
DEBUG:paramiko.transport:EOF in transport thread
DEBUG:paramiko.transport:Traceback (most recent call last):
DEBUG:paramiko.transport: File
"/usr/local/lib/python2.7/dist-packages/paramiko/transport.py", line 1426, in
run
DEBUG:paramiko.transport: ptype, m = self.packetizer.read_message()
DEBUG:paramiko.transport: File
"/usr/local/lib/python2.7/dist-packages/paramiko/packet.py", line 335, in
read_message
DEBUG:paramiko.transport: header = self.read_all(self.__block_size_in,
check_rekey=True)
DEBUG:paramiko.transport: File
"/usr/local/lib/python2.7/dist-packages/paramiko/packet.py", line 230, in
read_all
DEBUG:paramiko.transport: raise EOFError()
from Paramiko. We extended the wait_period manually but adding retry logic here
for the connect, and each of the sftp calls makes sense. Otherwise the external
deploy_node retry just results in having multiple nodes with the same exact
race condition.
> deploy_node(..) occasionally fails on EC2
> -----------------------------------------
>
> Key: LIBCLOUD-532
> URL: https://issues.apache.org/jira/browse/LIBCLOUD-532
> Project: Libcloud
> Issue Type: Bug
> Components: Compute
> Environment: apache-libcloud 0.14.1, Windows 7
> Reporter: Stefan Müller
>
> h2. Observed behaviour:
> When I'm starting EC2 nodes with {{deploy_node(ssh_key=...)}} I occationally
> (about 50% of the time) get a an error message indicating that my key is not
> a valid DSA key.
> This seems a bit odd, since I'm using an RSA key.
> h2. Cause
> Turns out the cause is somewhere else:
> When starting a node, there is a short time during which the SSH daemon is
> already up and running, but the public-key has not yet been put into the
> `authorized_keys` file. Apparently the SSH daemon is started before Amazon's
> key-injection magic has finished.
> During this short time (I'd guess about a second) SSH is rejecting the
> private key, with an authentication error.
> libcloud then tries some other means of authentication during which it
> apparently tries to parse the key as a DSA key, causing the reported error.
> Note that the extra-long timeout used for the SSH connection attempt is not
> helping in this case, since the SSH server is replying already.
> h2. Suggested Fix
> I suggest to react to a failed authentication with a few retries, with a
> second or two delay between them. Similarly to {{wait_until_running()}}.
> h2. Workaround
> {code}
> deploy_node(...,ssh_alternate_usernames=["root" for _ in range(10)])
> {code}
> This causes libcloud to make several authentification attempts. It is slow
> enough to delay until the public-key is in place. Solves the problem
> reliably, but not elegantly :)
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