Content Replication

Under the zone Configuration page is a category called Content Replication. This category represents the settings that are available in ZENworks Linux Management for sending administered content throughout the system.

Content replication in ZENworks Linux Management uses ZENworks Tiered Electronic Distribution.

ZENworks Tiered Electronic Distribution

ZENworks Linux Management takes advantage of a transmission technology that was originally developed by the traditional ZENworks product line. This technology allows for very efficient and controlled distribution of content to any server in the network.

Tiered Electronic Distribution (TED) is used by ZENworks Linux Management to effectively transmit all RPM packages from the ZENworks primary server to all secondary servers. For example, TED transmits to secondary servers only updates to the RPM packages, and does not send any packages that have already been copied to the secondary servers.

TED also has a check-point restart feature, where if the connection drops between the source and destination server, TED resumes the content transmission when the connection is restored, without retransmitting any data that was already sent.

NOTE

TED synchronizes content only one way: from the source to the target servers. That is why package management in ZENworks Linux Management must be done on the primary server. It always is treated as the source, whereas all secondary servers are considered the targets.

Configuring Synchronization

To configure when ZENworks should synchronize the secondary servers with the package content on the primary server, execute the following steps:

1.	Open ZENworks Control Center in your browser.
2.	Log in as an administrator.
3.	Click on the Configuration tab at the top of the ZENworks Control Center. This brings up the Management Zone Settings page. See Figure 12.1 for a sample page. Figure 12.1. Sample Management Zone Setting page.
4.	Click on the Content Replication setting. This brings up the page to make this setting. See Figure 12.2 for an example. Figure 12.2. Example of the Content Replication settings page.
5.	Click on the desired schedule type. The options include the following: No Schedule Date Specific Day of the Week Specific Monthly The various scheduling types are described in more detail in the following sections.
6.	Select Close to have the schedule applied.

After the scheduled event occurs, ZENworks dynamically creates a TED relationship between the primary server and the secondary servers. Then it gathers all changed or new packages, compresses them, and sends them to the secondary servers.

The secondary servers, after they receive the compressed content, extract the files and place them appropriately on the secondary server.

No Schedule Type

The No Schedule type prohibits content replication from occurring. This is the default schedule when the ZENworks Linux Management system is installed.

Date Specific Schedule Type

With the Date Specific schedule type you can identify a selected date or dates in the year when you want this action to occur. When you select Date Specific, the screen displays the page illustrated in Figure 12.3.

Figure 12.3. Date Specific scheduling page.

On the Date Specific schedule page you can enter the following information:

Start Dates Press the plus icon. This brings up the pop-up calendar dialog (see Figure 12.4) where you can select the date you want. To change the month, click on the diamond next to the month. To change the year, click on the diamond next to the year. After you have selected your date, the dialog automatically closes and the selected date appears in the Start Dates list.
Figure 12.4. Date Picker dialog for selecting a specific date of the year.

To remove the date, select the date in the Start Dates and press the minus icon.
Run Event Every Year Select the check box to cause content replication to occur every year on the selected dates.
Select When Schedule Execution Should Start In this area you can select whether the replication should occur at the given start time, or whether the execution should occur randomly between a given start and end time.
Enter the start time when you want the replication to begin. Enter the stop time, if you selected that the execution should occur randomly.
Select whether the time entered should be interpreted as Greenwich Mean Time (or Universal Time). Otherwise the system assumes you mean the local time of the primary server.

Day of the Week Specific Schedule Type

The Day of the Week schedule enables you to select a particular day of the week, along with some time schedules when you want the content replication to occur. Complete the following sections to identify your day of the week schedule. Figure 12.5 is an example of this type of schedule.

Figure 12.5. Day of the Week Specific schedule page.

SELECT THE DAYS OF THE WEEK

The first items to select are the days of the week when you want the content replication processes to run. Select the days of the week by clicking on the check box under your desired days.

RESTRICT SCHEDULE TO THE FOLLOWING DATE RANGE

Select the Restrict Schedule Execution to the Following Date Range check box if you want the system to perform the scheduled activity only during a specified calendar range. Then enter a start and end date by selecting the calendar browse button and picking the date on the pop-up calendar view.

SELECT WHEN SCHEDULE EXECUTION SHOULD START

This area enables you to select the time or time range when you want the content replication process to begin, on the days that you have specified earlier.

Choose one of the following options:

Start Immediately at Start Time This activates the content replication system at the specified start time.
Start at a Random Time Between Start Time and End Time This choice generates a random time that is between the start and end times. Then the content replication process begins at that randomly selected time.
Start Immediately at Start Time, and Then Repeat Until End Time This option starts the content replication process at the specified start time. Then it relaunches the content replication process at the interval specified in the Hours and Minutes fields. The system continues to relaunch the process at the interval specified until the end time is reached.

NOTE

Subsequent launches of the content replication process result in only files that have changed since the previous replication process being sent to the secondary server.

Next, specify your start time and end time. Select the hour and minutes from the drop-down list and then choose a.m. or p.m. Enter in both the start and end times.

Next, if the time you have specified is a Greenwich Mean Time or Universal Time rather than the local time of the primary server, check the check box next to the Use Greenwich Mean Time (GMT) option.

SET THE "BLACK OUT" TIME RANGES WHEN EXECUTION SHOULD NOT OCCUR

This option enables you to specify time ranges, which may fall within a calculated Start and End time. For example, imagine that you like to update your content every Saturday of the month. However, at the end of each business quarter you want your servers to work on end-of-quarter activities and not consume cycles transmitting package content. You can make this happen by entering your schedule and then selecting blackout dates for the end of each quarter. This way, if the calculated start time occurs within a specified blackout date, ZENworks does not launch the replication process. The content replication process is not started again until the next schedule time.

To enter blackout dates, complete the following:

1.	Press the Add menu item. A pop-up dialog box is presented (see Figure 12.6). Figure 12.6. Pop-up dialog to enter blackout dates and times.
2.	Enter the start date for the blackout period by selecting the calendar icon next to the Start Date field. This brings up the calendar pop-up, where you can select your date.
3.	Enter the start time when the blackout period will begin on the start date by clicking on the drop-down list next to this field and selecting a specific hour of the day.
4.	Enter the end date for the blackout period. This is initialized to be the same date as the chosen start date.
5.	Enter the time when the blackout period will end on the end date by selecting an hour from the drop-down list.
6.	Press the OK button to have the time entered as a blackout specification.

The entered blackout period is displayed on the screen. The blackout period begins at the specified time on the start date and ends at the selected end time on the end date.

To remove previously entered blackout periods, select the check box next to the listed blackout period and then click on the Remove menu item.

Monthly Schedule Type

The Monthly Schedule enables you to select which days of each month you want the content replication process to be launched.

First select the day of the month when you want the process to begin. This is done by choosing one of the following:

Start the scheduled event on a specific day of the month. This option starts the content replication on the given day of the month. Enter the numerical day of each month when you want the process to run.
Start the scheduled event on the last day of the month. This option starts the process on the last day of the current month.

Now select the time or time range when you want the content replication process to begin.

Choose one of the following options:

Start Immediately at Start Time This activates the content replication system at the specified start time.
Start at a Random Time Between Start Time and End Time This choice generates a random time that is between the start and end times. Then the content replication process begins at that randomly selected time.

Next, specify your start time and end time. This is accomplished by selecting the hour and minute from the drop-down list and then choosing a.m. or p.m. Enter in both the start and end times.

Next, if the time you have specified is a Greenwich Mean Time or Universal Time, rather than the local time of the primary server, check the check box next to the Use Greenwich Mean Time (GMT) option.

Now you can set out blackout times for your content replication.

The Black Out option enables you to specify time ranges, which may fall within a calculated Start and End time. If the calculated start time occurs within a specified blackout date, then ZENworks does not launch the replication process. The content replication process is not started again until the next schedule time.