MacLochlainns Weblog

I built a new image on VMWare Fusion for my class, which required installing MySQL 5.6 on Fedora, Version 20. If you don’t know how to add your user to the sudoers list, you should check this older and recently updated blog post.

1. Download the MySQL Yum Repository and launch the downloaded RPM.

2. Install MySQL on Fedora, Version 20, which you can find with the following command:

shell> rpm -qa | grep mysql
mysql-community-release-fc20-5.noarch

shell> sudo yum localinstall mysql-community-release-fc20-5.noarch.rpm

3. Install MySQL on Fedora with the following command:

shell> sudo yum install mysql-server

4. Start the MySQL service on Fedora with the following command:

shell> sudo service mysqld start

5. Secure the MySQL installation with the following command:

shell> mysql_secure_installation

6. Set the MySQL Service to start with the Fedora operating system with the following command (not chkconfig):

shell> sudo systemctl enable mysqld.service

ln -s '/usr/lib/systemd/system/mysqld.service' '/etc/systemd/system/mysql.service'
ln -s '/usr/lib/systemd/system/mysqld.service' '/etc/systemd/system/multi-user.target.wants/mysqld.service'

7. Reset the MySQL configuration file to enable external connections through Port 3306 with the following changes to the my:

#socket=/var/lib/mysql/mysql.sock

shell> ifconfig

bind-address=nnn.nnn.nnn.nnn
port=3306

bind-address=localhost.localdomain
port=3306

bind-address=0.0.0.0
port=3306

8. Restart the mysqld service with the following syntax:

shell> sudo service mysqld restart

shell> sudo netstat –anp | grep 3306

tcp        0      0 127.0.0.1:3306          0.0.0.0:*               LISTEN      1311/mysqld

Go to this page if you want to install MySQL Workbench.

A couple students in one of my classes ran into a problem when competing Java threads tried to insert new rows in a table. They raised an error when they tried the DELAY keyword to avoid the race (collision) condition in an INSERT statement. It was simple to explain to them that the DELAY keyword doesn’t work with an InnoDB table. Any attempt throws the following error:

ERROR 1616 (HY000): DELAYED OPTION NOT supported FOR TABLE 'message'

Important Update: INSERT DELAYED is gone in MySQL 5.6.6 (announcement) and the whole issue comes down to synchronizing threads (some dislike the solution) or using the ON DUPLICATE KEY clause.

They retested their Java application after redefining the target table using the MyISAM engine. They found it worked but that’s a bad fix in Java (a brief Java/MySQL tutorial post). They really needed to synchronize the Java thread (line #22), leave out the DELAY keyword, and manage the table with the InnoDB engine. Here’s the modified Java code (by the way, they named their project VulcanTech if you’re wondering about the packages in the import statement):

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package vulcantech.vth.server.commands;
 
import java.io.IOException;
import java.net.Socket;
 
import vulcantech.vth.server.combeans.MessageBean;
 
public class MessageHandler implements Handler {
 
  @Override
  public void handleIt(Object... args) {
 
    MessageBean message = (MessageBean) args[0];
    Socket sock = (Socket) args[1];
 
    DatabaseConnection dbconnection = new DatabaseConnection();
 
    String update = new String("INSERT INTO message(message_timestamp, sender, recipient, message, checked) VALUES(\'" 
                  + message.getTimeStamp() + "\', \'" + message.getSender() + "\', \'" 
                  + message.getRecipient() + "\', \'" + message.getMessage() + "\', b\'0\')");
 
    synchronized (this) {
      dbconnection.executeUpdate(update);
    }
 
    try {
      sock.getOutputStream().write(1);
    } catch (IOException e) {
      e.printStackTrace();
    }
    dbconnection.close();
  }
}

Hope this helps those who encounter race conditions against MySQL when you’re writing Enterprise Java Beans (EJBs).

Somebody posted on a Gnome patching blog post for Fedora to let me know that the download URL was invalid. I poked around and it appears that the old Fedora URL at Red Hat’s site doesn’t work:

http://download.fedora.redhat.com/pub/fedora/linux

You now have to go the Fedora Project web site for the code archive, and it’s here:

http://archive.fedoraproject.org/pub/fedora/linux/

If somebody knows why they made the change without any fanfare, please post a note.

Working with a Fedora 16 VM for my students (next term) and found that the MySQL Server’s my.cnf file worked with a Linux socket as opposed to a listener port, and that several configuration options where missing from the file. Here’s the default /etc/my.cnf file after the package installation from the Red Hat site:

[mysqld]
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under different user or group,
# customize your systemd unit file for mysqld according to the
# instructions in http://fedoraproject.org/wiki/Systemd
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
 
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

Without rebuilding the log files, this seemed like the cleanest replacement for the MySQL Server my.cnf for a development instance running on Fedora 16. If you’ve other suggestions, please let me know.

[mysqld]
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under different user or group,
# customize your systemd unit file for mysqld according to the
# instructions in http://fedoraproject.org/wiki/Systemd
 
# Default directory.
datadir=/var/lib/mysql
 
# The TCP/IP Port the MySQL Server listens on.
# ------------------------------------------------------------
#   Find the machine's IP address with this command run as
#   the root user and use the port number specified in the
#   my.cnf file:
#   [root@localhost ~]# netstat -an | grep 3306
# ------------------------------------------------------------
 
bind-address=nnn.nnn.nnn.nnn
port=3306
 
# The Linux Socket the MySQL Server uses when not using a listener.
# socket=/var/lib/mysql/mysql.sock
 
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
 
# The default storage engine that will be used when creating new tables.
default-storage-engine=INNODB
 
# Set the SQL mode to strict.
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
 
# Set the maximum number of connections.
max_connections=100
 
# Set the number of open tables for all threads.
table_cache=256
 
# Set the maximum size for internal (in-memory) temporary tables.
tmp_table_size=26M
 
# Set how many threads should be kept in a cache for reuse.
thread_cache_size=8
 
# MyISAM configuration.
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=52M
key_buffer_size=36M
read_rnd_buffer_size=256K
sort_buffer_size=256K
 
# InnoDB configuration.
innodb_data_home_dir=/var/lib/mysql
innodb_additional_mem_pool_size=2M
innodb_flush_log_at_trx_commit=1
innodb_log_buffer_size=1M
innodb_buffer_pool_size=25M
innodb_log_file_size=5M
innodb_thread_concurrency=8
 
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

As always, I hope this helps somebody.

Back in September, I showed how to setup Oracle Database 11g XE on Fedora. It was straightforward more or less, but tonight I ran into a problem while working with the Oracle Stop Database menu option. When I selected it form the menu, I got the user must be in the DBA OS group to stop the database.

Since the database started automatically on boot and shutdown when closing the operating system, I missed this nuance in the setup. The screen shot for the error is:

Oracle Database 11g XE automatically creates an oracle user with a dba group. While the mclaughlinm user was in the wheel group and an authorized sudoer, the mclaughlinm user needed to also be in the dba group. That’s more tricky in Fedora 15 and 16 because they’ve removed the System menu and the options that let you install and modify users.

Here are the steps to add your user to the dba group. Open a terminal session, and launch the User Manager application with the following command:

system-config-users

You have to enter the root password to get this to work. Then, it launches the User Manager application. Click on the target user, and click the Properties button.

The User Manager application launches the User Properties dialog. Click on the Groups tab.

Scroll in the groups list to the dba group. Click the checkbox for the dba group and the OK button.

Now, you’ll be able to navigate to through the menu to Stop Database to shutdown and Start Database to restart the Oracle database.

Hope this helps a few folks.

Fedora 16 is clearly better than Fedora 15 but I found Menu Editing (Alacarte package) was broken in it because of a missing library dependency, and I’ve updated Fedora Bug 734442 with the work around. Here’s what’s wrong and how to fix it.

After installing the Menu Editing (Alacarte) package, you’ll encounter this error when trying to launch the menu editor:

MainWindow.py:19:<module>:Import Error: No module named gmenu

That error occurs because the gnome-menus-3.2.0.1-1.fc16.x86_64 is missing the /usr/lib64/python2.7/site-packages/gmenu.so library. So, I copied the version of gmenu.so from a Fedora 15 release as the root user. Naturally, at this point you’d test if it was fixed, I did. It wasn’t, and I got a new error:

MainWindow.py:19:<module>:Import Error: libgnome-menu.so.2: cannot open shared object file: No such file or directory

That error occurs because the gnome-menus-3.2.0.1-1.fc16.x86_64 is missing the /usr/lib64/libgnome-menu.so.2 symbolic link to the /usr/lib64/libgnome-menu.so.2.4.13 library. While the package meets the dependency check, the libraries fail the run time validation.

If digging in like this is all new to you, I’d recommend UNIX and Linux System Administration Handbook (4th Edition) (University of Colorado at Bolder folks) for the Linux stuff and The Quick Python Book, Second Edition for Python basics.

You can get a copy of the Fedora 15 package with the following command, which you should connect as the root user in navigate to the /tmp directory. Then, create a copy directory and change the /tmp/copy directory before running either of the next two commands.

Use this for 32-bit Installs

# wget http://archive.fedoraproject.org/pub/fedora/linux/releases/15/Fedora/i386/os/Packages/gnome-menus-3.0.1-1.fc15.i686.rpm

Use this for 64-bit Installs

# wget http://archive.fedoraproject.org/pub/fedora/linux/releases/15/Fedora/x86_64/os/Packages/gnome-menus-3.0.1-1.fc15.x86_64.rpm

That command only a copy of the RPM file, but the following converts it into an exploded directory. Assuming you created a copy directory in the /tmp directory, execute the following command from within the /tmp/copy directory. It will create a directory tree with the required files. After you copy the files, you can remove (rm) the copy directory from the /tmp directory.

Use this for 32-bit Installs

# rpm2cpio http://archive.fedoraproject.org/pub/fedora/linux/releases/15/Fedora/i386/os/Packages/gnome-menus-3.0.1-1.fc15.i686.rpm | cpio -ivd

Use this for 64-bit Installs

# rpm2cpio http://archive.fedoraproject.org/pub/fedora/linux/releases/15/Fedora/x86_64/os/Packages/gnome-menus-3.0.1-1.fc15.x86_64.rpm | cpio -ivd

You can now copy the files with these files. The target location differs between the 32-bit and 64-bit versions of the operating system.

Use this for 32-bit Installs

# cp /tmp/copy/usr/lib/libgnome-menu.so.2* /usr/lib
# cp /tmp/copy/usr/lib/python2.7/site-packages/gmenu.so /usr/lib/python2.7/site-packages

Alternatively, you can copy the following two files from any valid 32-bit Fedora 15 instance into a Fedora 16 instance, and manually create the symbolic link.

# /usr/lib/libgnome-menu.so.2.4.13
# /usr/lib/python2.7/site-packages/gmenu.so

Use this for 64-bit Installs

# cp /tmp/copy/usr/lib64/libgnome-menu.so.2* /usr/lib64
# cp /tmp/copy/usr/lib64/python2.7/site-packages/gmenu.so /usr/lib64/python2.7/site-packages

Alternatively, you can copy the following two files from any valid Fedora 64-bit 15 instance into a Fedora 16 instance, and manually create the symbolic link.

/usr/lib64/libgnome-menu.so.2.4.13
/usr/lib64/python2.7/site-packages/gmenu.so

After you copy the two files into the right directories as root, you can create the necessary symbolic link with the following command (this isn’t necessary with the wildcard instruction provided earlier in the post). You need to ensure that you’re in the /usr/lib directory when you run the ln command, as noted by Gavin’s comment:

Use this for 32-bit Installs

# ln -s /usr/lib/libgnome-menu.so.2.4.13 libgnome-menu.so.2

Use this for 64-bit Installs

# ln -s /usr/lib64/libgnome-menu.so.2.4.13 libgnome-menu.so.2

As mentioned by Darr247, don’t forget to remove the /tmp/copy directory when you’re done making the changes.

Somebody asked me to add the Red Hat Package Manager (RPM) commands that let me find these dependencies. That seemed like a good idea, here they are:

If you want to set a menu item up manually, check this blog post. You also have the LXMenuEditor that’s available in beta as an alternative. Hope this helps those in need, as always.

Somebody asked why adding a user to the wheel group in Oracle Enterprise Linux didn’t enable them as a sudoer, as qualified in my earlier Fedora post. The reason is that you also need to modify the /etc/sudoers file to specify users allowed that privilege (and the file differs from it’s Fedora cousin). If you have the root user privileges, you can do the following:

1. Change to the root user account with su, and provide the password when prompted. The syntax is:

su - root

2. You can find the line you need to change with this command:

cat /etc/sudoers | grep %wheel

# %wheel     ALL=(ALL)      ALL
# %wheel     ALL=(ALL)      NOPASSWD: ALL

Hope this helps, I’m off to Oracle Open World 2011 tomorrow.

Quick update for Fedora 20, you su to root and add your user to the sudoers list with the following syntax:

usermod someusername -a -G wheel

By the way, don’t forget to log off and then back on to the account.

It seems Fedora is always a bit of work. You begin by mistakenly downloading Fedora Live, which isn’t really the product but a run-time demonstration product. After finding the product, if you choose a full installation, there are post installation steps to complete. The first time you launch it in VMWare, you’ll see a Gnome 3 Failed to Load error dialog like this:

I suspected that installing VMWare Tools would fix that, and it did. However, your entry account doesn’t have “sudoers” permissions. You must add them before you can run VMWare Tools. There are six steps to enable your user with the sudoers permissions and four others to configure the standard installation:

1. Navigate to the Applications menu choice in the upper left hand corner. You’ll get the following drop-down menu. Click on Other menu item to launch a dependent floating menu.

2. The following floating menu displays to the right. Click on Users and Groups menu item at the bottom of the list.

3. The choice from the floating menu prompts account validation. Enter your password and click the OK button.

4. After validating your password, the User Manager dialog opens. Click on the single user that should be installed – mclaughlinm. Click the Properties button to change the groups assigned to the user.

5. The User Properties dialog opens with the default User Data tab clicked. Click on the Groups tab to add the user to the wheel group as a property of your user.

6. Scroll down through the list of groups and click the wheel group check box. Like the Mac OS, the wheel group provides “sudoer” privileges. Click the OK button to assign the group to the user.

7. Navigate to the VMWare Menu, choose Virtual Machine and in the drop down menu Install VMWare Tools. This will mount a virtual CD in the Fedora virtual machine.

8. Navigate to the Places menu choice and then Computer. Inside the Computer, choose the VMware Tools from the Devices section and you’ll see the following:

9. Open a terminal session by choosing Applications, within the drop down choose System Tools, and then launch a Terminal session. You can then run the VMWare Toolkit by following these instructions:

cd /media/VMware\ Tools
cp VMwareTools-8.4.7-416484.tar.gz /tmp
cd /tmp
gunzip VMwareTools-8.4.7-416484.tar.gz
tar -xvf VMwareTools-8.4.7-416484.tar
cd vmware-tools-distrib
sudo ./vmware-install.pl

sudo ./vmware-install.pl --default

sudo yum-complete-transaction

10. In the terminal session you should configure three files to make sure your networking works. I found that the dialogs failed to set one key element, so it’s simply easier to do this manually. Rather than using sudo, you should open a root shell with the following command:

sudo sh

[sudo] password for mclaughlinm:

# Generated by NetworkManager
domain localdomain
search localdomain
nameserver 172.16.123.2

NETWORKING=yes
HOSTNAME=localhost.localdomain
GATEWAY=172.16.123.2

DEVICE=eth0
HWADDR=00:0c:29:31:ef:46
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=dhcp
TYPE=Ethernet
DNS1=172.16.123.2
USERCTL=no
PEERDNS=yes
IPV6INIT=no

/etc/rc.d/init.d/network restart

As always, I hope this helps a few folks.

Bash shell or shells in general hang on details. An ex-student was trying to sort something out in Learning the bash Shell, 3^rd Edition, which isn’t on my short list of good shell scripting books. I concur more or less with the comment on Amazon.com that there are too few examples in the book. I think the free examples here may serve folks in lieu of a book.

Anyway, the student’s problem involved processing multiple word parameters in an array. They were confused about how to handle ${*}, ${@} "${*}" and "${@}" when assigning them into an array for subsequent processing. By the way, I did find a decent explanation of the concept on Page 89 in my copy of the book. Though my copy is a 2^nd Edition.

Here’s a dressed up sample of what they were attempting to do:

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#!/bin/bash
 
# Print header information.
echo "Begin Program!"
echo ""
 
# Count the call parameters.
echo "Count call parameters [" ${#} "]"
echo ""
 
# Declare an array of delimited parameters.
ARRAY=(${@})
 
# Declare a numeric constant of array elements.
ELEMENTS=${#ARRAY[@]}
 
# Does the parameter account agree with array elements.
if [[ ${#} = ${#ARRAY[@]} ]]; then
  echo "Parameters match exploded array elements."
else
  echo "Parameters ["${#}"] don't match exploded array elements ["${ELEMENTS}"]."
fi
 
# Echo line break.
echo ""
 
# Echo the parameter list.
for (( i = 0; i < ${ELEMENTS}; i++ )); do
  echo "  ARRAY["${i}"]=["${ARRAY[${i}]}"]"
done
 
# Print footer information.
echo ""
echo "End Program!"

With the ARRAY=(${@}) assignment on line #12, they exploded the elements into individual words. They thought that the IFS (Internal Field Separator) environment variable was defined wrong but it wasn’t.

They called the program like this from the command-line:

sample.sh "Me too" "You too"

Then, they got this syntax and were surprised.

Begin Program!
 
Count call parameters [ 2 ]
 
Parameters [2] don't match exploded array elements [4].
 
  ARRAY[0]=[Me]
  ARRAY[1]=[too]
  ARRAY[2]=[You]
  ARRAY[3]=[too]
 
End Program!

They were close. The ARRAY=(${@}) assignment on line #12. There attempt to fix it with ARRAY=(${*}) led nowhere because it’s more or less the same and explodes into 4 words. To their credit, they put quotes around it like this ARRAY=("${*}") and got two parameters but one array element, as shown below:

Begin Program!
 
Count call parameters [ 2 ]
 
Parameters [2] don't match exploded array elements [1].
 
  ARRAY[0]=[Me too You too]
 
End Program!

What they needed was ARRAY=("${@}") on line #12 to explode quote delimited parameters. Here’s a complete working example of the final code.

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#!/bin/bash
 
# Print header information.
echo "Begin Program!"
echo ""
 
# Count the call parameters.
echo "Count call parameters [" ${#} "]"
echo ""
 
# Declare an array of delimited parameters.
ARRAY=("${@}")
 
# Declare a numeric constant of array elements.
ELEMENTS=${#ARRAY[@]}
 
# Does the parameter account agree with array elements.
if [[ ${#} = ${#ARRAY[@]} ]]; then
  echo "Parameters match exploded array elements."
else
  echo "Parameters ["${#}"] don't match exploded array elements ["${ELEMENTS}"]."
fi
 
# Echo line break.
echo ""
 
# Echo the parameter list.
for (( i = 0; i < ${ELEMENTS}; i++ )); do
  echo "  ARRAY["${i}"]=["${ARRAY[${i}]}"]"
done
 
# Print footer information.
echo ""
echo "End Program!"

Changing that one element yields their desired output:

Begin Program!
 
Count call parameters [ 2 ]
 
Parameters match exploded array elements.
 
  ARRAY[0]=[Me too]
  ARRAY[1]=[You too]
 
End Program!

As always, I hope this helps some folks.

Rebuilding new reference environments on my MacPro, I started with Ubuntu 10.04.01 LTS (64 bit), I had to recall the step to install VMWare Tools. It’s quite simple but I know my students may need the steps to configure a VMWare virtual machine and it may benefit others. While this Ubuntu help page is a good start it isn’t a step-by-step configuration guide.

1. Navigate to the VMWare Menu, choose Virtual Machine and in the drop down menu Install VMWare Tools. This will mount a virtual CD in the Ubuntu virtual machine.
2. Open a terminal session by choosing Applications, within the drop down choose Accessories, and in the subsequent drop down choose Terminal. It will launch a terminal session for command-line entry. The screen shot will look like the following.

3. From the command-line perform the following tasks:

cd /media/VM*
cp VMwareTools*.gz /tmp
cd /tmp
gunzip VMwareTools*.gz
tar -xvf VMwareTools*.tar
cd vmware-tools-distrib
sudo ./vmware-install.pl

4. After starting the vmware-install.pl, accept all the default prompts. Alternatively, as Josh points out enter the following to skip the prompts:

sudo ./vmware-install.pl --default

5. After the configuration completes, you’re prompted to restart the X-Windows. The easiest way is to reboot. You click on the upper right corner to get the drop down menu to restart Ubuntu. A screen shot follows.

This completes the VMWare Tools installation on Ubuntu but unfortunately, you may need to setup the network connection. In a couple instances, the Ubuntu installation appears to have corrupted the VMWare networking process. The result is that the DNS setup on Ubuntu didn’t work.

When the Ubuntu /etc/resolv.conf file is empty. You should first restart the VMWare network. This can be done without rebooting your native Mac OS X. Open a Terminal session, and navigate to the following directory and restart the VMWare network or use this command with backquoting.

sudo /Library/Application\ Support/VMware\ Fusion/boot.sh  --restart

If your Ubuntu /etc/resolv.conf file is empty, you can manually edit it. The last line in this sample depends on your IP subnet. I’ve entered it by assuming that you’re on 192.168.75.0 to 192.168.75.255 with a 255.255.255.0 network mask. You can refer to this prior post for the details on how you find your VMWare NAT subnet.

When your Ubuntu /etc/resolv.conf file is empty, add these values:

# Generated by NetworkManager
domain localdomain
search localdomain
nameserver 192.168.75.2

Hope this helps some folks.