Iain Samuel McLean Elder's questions

I'm trying to set up a Linux development environment so I can safely make changes to my website without breaking the live site.

Linode hosts my live site. A simple solution would be to host my development server on Linode as well, but I want to avoid doubling my hosting costs.

The cheapest way I see is to use Vagrant on my Windows workstation to host my development environment.

After I attempt to restore the backup to Vagrant and reboot the VM, I can no longer ssh into the Vagrant host.

It's probably because by restoring the backup I overwrite some special Vagrant configuration, but I'm not sure how to avoid that.

How do I make this approach work? If my approach is fundamentally wrong, can you suggest an alternative?

Creating the backup

On the Linode I used these commands to create a compressed copy of the entire filesystem, while ignoring things that shouldn't be included in the backup:

$ sudo rsync -ahvz --exclude={/dev/*,/proc/*,/sys/*,/tmp/*,/run/*,/mnt/*,/backup/*} /* /backup/2
$ sudo tar -czf /backup/2.gz /backup/2

The backup file is called 2.gz because this is thesecond backup. The first backup is called 1.gz.

I use WinSCP to copy the backup file to my Windows workstation.

Setting up the Vagrant host

I need a Vagrant box that matches my Linode operating system (Ubuntu 12.04.3 LTS, kernel 3.9.3). I selected the closet match from vagrantbox.es:

Ubuntu Server Precise 12.04.3 amd64
Kernel is ready for Docker (Docker not included)

On my workstation I ran these commands to add the box and initialize and boot an instance:

$ vagrant box add ubuntu-precise http://nitron-vagrant.s3-website-us-east-1.amazonaws.com/vagrant_ubuntu_12.04.3_amd64_virtualbox.box
$ mkdir linode-test
$ cd linode-test
$ vagrant init ubuntu-precise
$ vagrant up

Now Vagrant is running a machine with SSH on port 2222.

The operating system version is the same. The kernel version is 3.8.0. Sounds close enough.

Restoring the backup

With WinSCP I copied the backup file 2.gz to /home/vagrant/2.gz on the Vagrant box.

With PuTTY I connected via ssh to my new Vagrant box:

On the box move the backup to the filesystem root.

$ sudo mv 2.gz /

Extract the archive to the filesystem root:

$ sudo tar -xvpz -f 2.gz -C / --strip-components=2

(I discovered I need to use strip components because all files in the archive have the prefix backup/2/. I'll fix this for the next backup.)

After the tar command completes, I log out of the box.

Testing the backup

When I try to log in again, it doesn't let me log in as vagrant with a password any more.

It does let me log in as iain, my user on the live Linode, with a password. That surprised me because I disabled password authentication on my live Linode. I figured that I have to restart the ssh service for the change to take effect.

Instead of restarting just ssh, I chose to restart the whole system.

Now I can't even get to the login screen. PuTTY says "connection refused" when I try to connect.

What went wrong?

The problem

The CKAN installation documentation shows you how to list the installed PostgreSQL databases.

The command looks like this:

sudo -u postgres psql -l

When I try that in my shell, I get an error:

$ sudo -u postgres psql -l
sudo: psql: command not found

The workaround

Daniel2d2art on the CentOS forum worked around the problem by fully qualifying the path to psql.

My psql lives in the directory /usr/pgsql-9.2/bin, so my workaround now looks like this:

sudo -u postgres /usr/pgsql-9.2/bin/psql -l

When I try that in my shell, it works:

$ sudo -u postgres /usr/pgsql-9.2/bin/psql -l
                                   List of databases
     Name     |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges
--------------+----------+----------+-------------+-------------+-----------------------
 postgis_test | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 postgres     | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 template0    | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
              |          |          |             |             | postgres=CTc/postgres
 template1    | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
              |          |          |             |             | postgres=CTc/postgres
(4 rows)

How do I fix it properly?

I shouldn't have to fully qualify the path, right?

The postgres user already has psql in its path:

$ sudo -u postgres echo $PATH
/usr/pgsql-9.2/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin

How do I fix this properly?

On my SQL Server instance I use SQL Agent to run a daily backup job in two steps.

One of the steps uses Robocopy to move local backup files to network storage.

The command to move the files looks like this:

robocopy M:\backups \\NAS\backups$\Database /MOV /MIR /XJ /NP /COPY:DT

The output of the command in the job step history looks like this:

-------------------------------------------------------------------------------     
ROBOCOPY     ::     Robust File Copy for Windows                                
-------------------------------------------------------------------------------      
Started : Fri Jul 20 00:55:42 2012     
Source : M:\backups\       
Dest : \\NAS\backups$\Database        
Files : *.*            
Options : *.* /S /E /COPY:DT /MOV /PURGE /MIR /NP /XJ /R:1000000 /W:30     
------------------------------------------------------------------------------  
3  M:\backups\
      *EXTRA File       15.5 m  GeoDisplay_Full_2012-07-19-000004.bak
      *EXTRA File       41.3 m  GeoDisplay2_Full_2012-07-19-000004.bak
      *EXTRA File      264.1 g  Webstore_Full_2012-07-19-000004.bak
      New File          15.5 m  GeoDisplay_Full_2012-07-20-000002.bak
      New File          41.4 m  GeoStore_Full_2012-07-20-000002.bak
      New File         302.1 g  Webstore_Full_2012-07-20-000002.bak

      2012/07/20 04:34:50 ERROR 32 (0x00000020) Deleting Source File M:\backups\Webstore_Full_2012-07-20-000002.bak  The process cannot access the file because it is being used by another process.       
------------------------------------------------------------------------------
      Total    Copied   Skipped  Mismatch    FAILED    Extras
Dirs :         1         0         1         0         0         0     
Files :         3         3         0         0         0         3     
Bytes : 302.187 g 302.187 g         0         0         0 264.181 g     
Times :   3:38:57   3:38:45                       0:00:00   0:00:11         
Speed :            24720063 Bytes/sec.     
Speed :            1414.493 MegaBytes/min.       
Ended : Fri Jul 20 04:34:50 2012.  
Process exit code 3.

The text output clearly shows ERROR 32. Robocopy failed to honor the /MOV switch (delete from source after copy) because another process had a handle on one file when robocopy tried to delete it.

Robocopy returned exit code 3 (new files copied to destination and extra files deleted from destination). This is correct but incomplete because there is no way to tell from the error code that any operation failed.

SQL Agent considers only the return code, not the command output, when determining the success of a command shell operation. I could modify the Robocopy command to save the output to disk, and parse the output in an extra job step, but this requires extra programming and would add another dependency to the backup job.

Is there any way to detect this kind of failure without searching Robocopy's text output for the string ERROR 32?

In the root of my drive there exists a folder called SourceControl that contains all the working copies of all my programming projects.

I would like to move the folder to my user directory (\Users\Me), but something about the permissions on the folder forbids me. I don't remember how I created the folder.

When I execute the move command:

MOVE \SourceControl \Users\Me

I receive the following error:

Access is denied.

I have resolved a similar problem in the past using the Takeown utility to assign ownership of the file to me, so I tried this command next:

TAKEOWN /F \SourceControl

It returns the following error:

ERROR: The current logged on user does not have ownership privileges
       on the file (or folder) "C:\SourceControl".

I've just learned about the Icacls utility, which can inspect and modify file permissions.

I used this command to inspect the permissions on the folder:

ICACLS \SourceControl

It produced this list:

\SourceControl BUILTIN\Administrators:(I)(F)
               BUILTIN\Administrators:(I)(OI)(CI)(IO)(F)
               NT AUTHORITY\SYSTEM:(I)(F)
               NT AUTHORITY\SYSTEM:(I)(OI)(CI)(IO)(F)
               BUILTIN\Users:(I)(OI)(CI)(RX)
               NT AUTHORITY\Authenticated Users:(I)(M)
               NT AUTHORITY\Authenticated Users:(I)(OI)(CI)(IO)(M)

I think this means that normal user accounts, like mine, have permission only to read and execute (RX) here, while administrator accounts have full control (F).

I used Icacls to confer full control of the directory to my user account with this command:

ICACLS \SourceControl /grant:r Me:F

The command produces this output:

processed file: \SourceControl
Successfully processed 1 files; Failed processing 0 files

Now inspection of the permissions produces this output:

\SourceControl Domain\Me:(F)
               BUILTIN\Administrators:(I)(F)
               BUILTIN\Administrators:(I)(OI)(CI)(IO)(F)
               NT AUTHORITY\SYSTEM:(I)(F)
               NT AUTHORITY\SYSTEM:(I)(OI)(CI)(IO)(F)
               BUILTIN\Users:(I)(OI)(CI)(RX)
               NT AUTHORITY\Authenticated Users:(I)(M)
               NT AUTHORITY\Authenticated Users:(I)(OI)(CI)(IO)(M)

But after this the move command still fails with the same error.

Is it possible to move this folder without invoking administrator rights? If not, how should I do it as administrator?

I'm trying to debug an application that uses Microsoft Message Queuing (MSMQ). I can debug the queues on my development server using a remote desktop connection, but can't repeat the process on my local desktop. I would prefer to use an application on my local desktop if possible.

My development server is running Windows Server 2003 R2 Enterprise Edition. My local machine is running Windows 7 Professional Edition.

To debug the queues using a remote desktop connection (see first screenshot):

1. Connect remotely as DEV\admin_me to the desktop of my development server (DEVSERVER).
2. Run compmgmt.msc.
3. Navigate to 'Computer Management (Local) > Services and Applications > Message Queueing > Private Queues' to see the two private queues used by my application.

To repeat the process on my local desktop (see second screenshot):

1. Run runas /user:DEV\admin_me "mmc compmgmt.msc /computer:\\DEVSERVER". (Use runas because my local desktop account is DEV\me, not admin).
2. Try to navigate to 'Computer Management (DEVSERVER) > Services and Applications > Message Queueing', but it is not visible.

Am I missing something, or is using a remote desktop connection the only way?

On my development machine I run Ubuntu 10.04.1 LTS. Following the official documentation, I used the following command to install Apache, MySQL and PHP in one go:

sudo tasksel install lamp-server

Now that I'm testing my PHP scripts, I want to enable "developer mode", if there is one, to enable error reporting and logging. I have read reference to files php.ini-production and php.ini-development that apparently come with some versions of PHP 5, but not the one I have installed.

All I have is /etc/php5/apache2/php.ini. This configuration does not echo errors or warnings, which makes my scripts hard to debug. I guess I can edit the configuration by hand, but I'd rather just be able to drop in a replacement if that's possible.

So what I'm looking for is an easy way to switch between development and production environments for PHP!

We run Apache version 2.2.8-1ubuntu0.15 on our VPS instance of Ubuntu 8.04.4 LTS \n \l, as I determined by asking this question.

When I issue pgrep apache2, I get the following:

 2691
24517
25330
25669
25672
25795
25796
25809
25825
26401
26402

That's 11 seperate instances of apache2! Is this normal? If not, what should I do about it?

I've just taken over webmastery for my company's site, and I'm preparing a report for my partner about the LAMP stack. But I'm a new CS graduate, and the only thing I know really well is Java coding, so I need some help!

I'm trying to find out a) if Apache is installed and b) what version is running.

My Linux version is "Ubuntu 8.04.4 LTS \n \l", as reported by /etc/issue.