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= Alerts =
An alert is the method Landscape uses to notify its administrators of special conditions that require attention. Alerts are displayed in several places throughout the Landscape web interface, the most prominent one being the dashboard, and can even be sent as e-mails.

Below is an example showing some alerts in the Dashboard area of Landscape:


As we can see, there are several different types of alerts available, and future versions of Landscape may add more. Let's see more details about each type of alert.

= Types of alerts =
These are the types of alerts currently available in Landscape:
 * security updates: whenever there are new security updates available
 * package updates: whenever there are new package updates available. This includes the security updates, if any.
 * computer offline: if a computer does not ping the Landscape server for more than five minutes, this alert is triggered. This timeout is not yet configurable.
 * pending computer: whenever there is a pending computer which needs to be accepted or rejected
 * unapproved activity: whenever there is an activity which requires and explicit administrator action to either accept or reject it
 * reboot needed: alerts whenever a computers needs to be rebooted as a result of a package upgrade such as the kernel

= Selecting to which computers alerts apply =
By default, all alerts apply to all computers in your account. This is a safe default and means that administrators will be warned of important issues concerning the managed machines.

It may be desirable, however, to select which types of alerts apply to which computers. This can be accomplished through the use of tags. Let's see an example.

/!\ Note it's not possible to use tags for the "Pending Computer" alert because these computers don't have tags yet and are not part of the account until they are accepted

Here is the package update alert:


If we click on the "edit" link, we can select to which tags this alert applies:


In this example, we have only one tag, and by default "All computers" is selected. If we select the "vm" tag instead, the alert will only be triggered if computers with that tag present package upgrades.

= Subscribing to alerts =
Alerts can also be sent via e-mail to administrators who chose to subscribe to them. Every 30min the Landscape server checks for such subscriptions and sends the alerts.

Subscribing to an alert is easy. In the alerts page, just check the box for the type of alert you want to subscribe to. For example, let's subscribe to the "package upgrades" alert:


After selecting the alert and clicking on "Subscribe", we get this result:


Now whenever a new package upgrade becomes available and this alert is triggered, at most 30min later an e-mail will be sent to this administrator. This is what an e-mail about a security update alert looks like, for example:


= Usage considerations =
It may be tempting at first glance to subscribe to all alerts. In the case of package related alerts, we need however to consider a few things first to try to minimize the number of e-mails an administrator will get.

In general, keep in mind the following:
 * package upgrades can become available at any time, any day, for any machine
 * even similar machines, with similar deployments, may become aware of updates in different times
 * e-mail alerts are sent out only every 30min

== Several computers with similar installations ==
If you have machines with similar or identical packages installed, and package upgrade alert e-mails are enabled, you may find that you are getting e-mails about the same updates over and over, and in waves.

This happens because, as each machine becomes aware of the available upgrades, it sends this information to the Landscape server. The server then accumulates these every 30min and sends them out. It's very likely that some machines missed this 30min window and their e-mail alert will be sent out in the next one, and so on.

This is a bit unfortunate. On one hand we want to be notified as soon as possible about available upgrades. But on the other hand, being too quick can lead to some machines missing our alert window and making Landscape send their specific alert in a subsequent e-mail.

One suggestion would be to only enable this alert for one or two machines that can be considered as representative of the others. In that way, only one or two e-mails would be sent, but the administrator would need to remember that other machines are affected too.

== Computers recently accepted into Landscape ==
When a computer is registered with Landscape, it starts to upload its data to the server. Uploading package data happens in batches of 500, and for clients older than, it may take several hours to complete this process.

As package data is being uploaded, upgrades may become available even before the whole process finishes. For example, in the first batch of 500 packages, 2 may be upgrades. That will trigger an alert and, if there are subscriptions for it, e-mails will be sent. Another batch uploaded later may contain more upgades, which will retrigger the alert and send another e-mail. And so on, until the whole upload is finishes.

In short, while a computer is synchronizing its package list with Landscape for the first time, several e-mail alerts may be sent.

Starting with the client, this effect is minimized because this client can sync up its package list much faster, typically in less than 30min, which means less alert e-mails would be sent.