- - Out-of-band management
allows for console access to remote servers. This level of access is
just like standing in front of the server. Using a web browser you can
see error messages on the server console and boot up from media like
CDROMs and USB sticks. Normally, you will have a dedicated network card
available for this service. From a security point of view, I recommend
that you connect this network card to a secure management network which
is protected with access control lists.
- - In-band management allows you to get remote desktop access once an
operating system has finished its boot up process. An example of this is
the Microsoft Remote Desktop Protocol service (RDP). Just make sure
your servers are fully patched as vulnerabilities do exist with the RDP service.
- - Deploying servers as virtual machines allow you to change settings
like memory and CPU allocations remotely. Most virtual platforms will
also report on how each virtual machine is performing so that you can
take the appropriate action when things get busy. The one thing to watch
with this approach is that some applications, especially databases,
will run better on physical servers. This is due to the large volumes of
data reads and writes which can slow down when travelling across virtual infrastructures.
- - Network monitoring standards like SNMP and WMI
allow you to gather performance metrics which can be then stored in a
central location. Data is normally collected in two ways. Firstly, a
network monitoring tool will periodically check metrics like CPU or
memory usage. This data can then be trended so that you can spot when
something is getting overloaded. Secondly, remote servers can be
configured to send alerts when something goes wrong. You will normally
find out about problems quicker when the server sends the alert. I
covered this topic in more detail in a previous blog post which looked
at ways for managing a network more efficiently.
- - So far I have looked at ways for monitoring and managing remote servers and applications. It is also important to know what is happening on remote LANs. You can gather some network performance information using SNMP but I find that this data is better for WAN management. Traffic analysis tools can be used to troubleshoot problems by looking at network traffic. There are two main technologies available in this space, those that do flow analysis and those that capture network packets. Flow statistics are normally available from devices that can route data between two networks. If your remote networks are flat (single subnet) or you don't have flow options on your network switches then packet capture is an option. Packet capture operates by connecting a traffic analysis system to a mirror port on a network switch. The mirror port will then send a copy of the network traffic going to and from any server or device that you are interested in to the traffic analysis application.