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Steve's questions

Martin Hope
Steve
Asked: 2012-05-22 11:12:28 +0800 CST
  • 1

I am running a play framework java application in a linode instance. My virtual host entry looks as follows.

<VirtualHost *:80>
  ProxyPreserveHost On
  ServerName www.example.com
 <Proxy *>
    Order Allow,Deny
    Allow From All
 </Proxy> 
 ProxyPass / http://127.0.0.1:9000/
 ProxyPassReverse / http://127.0.0.1:9000/
</VirtualHost>

Now I want to install a wordpress blog and access it from www.example.com/blog. I have copied the wordpress folder to /var/www/blog. I am not able to access the URL www.example.com/blog as the request is going to the play framework. I would like to know how to resolve this.

Thanks in advance.

apache-2.2 wordpress
Martin Hope
Steve
Asked: 2012-02-09 05:54:06 +0800 CST
  • 1

We are a small startup. In our current setup we have a dedicated server in a remote location. Our website and applications are hosted in that server. Website and some applications are in PHP and the rest are java applications using Tomcat and JBoss. Our database server is mysql. We backup mysql data to our local server using replication. Obviously thing can go wrong in multiple ways in this setup and they have. We had some serious downtime issues and other scares recently.

The new setup we have in mind is as follows.

1) Buying a new server with the same configuration as the current one. Setting this up similar to the current server with all the apps and software

2) Doing hot backup to the new server using BackupPC. (syncing only the often changing files like website, php apps, jboss and tomcat apps)

3) Running a mysql slave in the new server with semi-synchronous replication

4) Running apache/nginx/lighttpd as a reverse proxy in a separate server that points to the primary server.

5) Continue to run a slave in the local server

In case of downtime we can point the reverse proxy to the secondary server. We don't want to do automatic failover, because we have to make sure that the secondary server is fully synced before pointing to it.

What are the pros and cons of the above approach? Or how this can be improved? I understand the reverse proxy will be a SPOF. At this point we are looking for a cost effective solution. Can the reverse proxy be a low priced server with somewhat decent configuration?

I just put this together by reading various articles. It is possible that some of my understandings are wrong. Please feel free to correct them.

small-business high-availability reverse-proxy
Martin Hope
Steve
Asked: 2011-11-08 07:19:16 +0800 CST
  • 4

I am trying to connect to our remote server using winSCP. It was working before. But from today I am not able to connect to the server using SFTP. If I changed the protocol to SCP, then I am able to connect. Also I am able to connect using putty.

Following is the winSCP log. (removed host details)

. 2011-11-07 20:18:54.593 Using SFTP protocol.
. 2011-11-07 20:18:54.593 Doing startup conversation with host.
> 2011-11-07 20:18:54.593 Type: SSH_FXP_INIT, Size: 5, Number: -1
. 2011-11-07 20:18:54.593 Server sent command exit status 127
. 2011-11-07 20:18:54.593 Disconnected: All channels closed
* 2011-11-07 20:18:54.624 (ESshFatal) Connection has been unexpectedly closed. Server sent command exit status 127.
* 2011-11-07 20:18:54.624 Cannot initialize SFTP protocol. Is the host running a SFTP server?
. 2011-11-07 20:31:40.036 Looking up host <<host name>>
. 2011-11-07 20:31:40.052 Connecting to <<ip>> port 22
. 2011-11-07 20:31:40.630 Server version: SSH-2.0-OpenSSH_5.8
. 2011-11-07 20:31:40.630 We claim version: SSH-2.0-WinSCP_release_4.1.6
. 2011-11-07 20:31:40.630 SSPI: acquired credentials for: <<username>>
. 2011-11-07 20:31:40.630 Constructed service principal name 'host/<<hostname>>'
. 2011-11-07 20:31:40.802 GSSKEX disabled: The specified target is unknown or unreachable

. 2011-11-07 20:31:40.802 Using SSH protocol version 2
. 2011-11-07 20:31:40.927 Doing Diffie-Hellman group exchange
. 2011-11-07 20:31:41.224 Doing Diffie-Hellman key exchange with hash SHA-1
. 2011-11-07 20:31:41.787 Host key fingerprint is:
. 2011-11-07 20:31:41.787 ssh-rsa 2048 b9:2a:b8:56:a0:72:ff:10:11:d2:3e:55:95:5f:54:e2
. 2011-11-07 20:31:41.787 Initialised AES-256 SDCTR client->server encryption
. 2011-11-07 20:31:41.787 Initialised HMAC-SHA1 client->server MAC algorithm
. 2011-11-07 20:31:41.787 Initialised AES-256 SDCTR server->client encryption
. 2011-11-07 20:31:41.787 Initialised HMAC-SHA1 server->client MAC algorithm
! 2011-11-07 20:31:42.068 Using username <<username>>.
. 2011-11-07 20:31:42.677 Keyboard-interactive authentication refused
. 2011-11-07 20:31:42.677 Prompt (6, SSH password, , &Password: )
. 2011-11-07 20:31:46.568 Sent password
. 2011-11-07 20:31:46.865 Access granted
. 2011-11-07 20:31:47.162 Opened channel for session
. 2011-11-07 20:31:47.475 Started a shell/command
. 2011-11-07 20:31:47.475 Doing startup conversation with host.
> 2011-11-07 20:31:47.475 Type: SSH_FXP_INIT, Size: 5, Number: -1
. 2011-11-07 20:31:47.475 Server sent command exit status 127
. 2011-11-07 20:31:47.475 Disconnected: All channels closed
* 2011-11-07 20:31:47.506 (ESshFatal) Connection has been unexpectedly closed. Server sent command exit status 127.
* 2011-11-07 20:31:47.506 Cannot initialize SFTP protocol. Is the host running a SFTP server?

Recent happenings.

For some reason our site was not accessible yesterday. We informed our host and they rebooted the server. This problem is happening only after that.

I have issued "locate sftp-server", it returns two locations.

/usr/libexec/openssh/sftp-server /usr/local/libexec/sftp-server

It looks like the second folder (/usr/local/libexec/sftp-server) is created/updated the day before yesterday. Also sshd-config file got updated on the same day. From the rpmpkgs logs, it looks like vsftpd also updated on the same date.

I suspected some auto update had happened. I checked the yum-updatesd.conf, but auto updates disabled there.

How to make sftp-server work again? In sshd-config the Subsystem is pointing to /usr/libexec/openssh/sftp-server. Should I change that to /usr/local/libexec/sftp-server?

Can I restart sshd from putty? I don't want to screw up the ssh connection also. I would like to solve this without rebooting the system again.

Please let me know if you want any more info. Thanks in advance

ssh sftp scp winscp