07-02-2008 04:34 AM
According to the CMS manual, using a virtual machine for the CMS system is not supported. Just wanted to confirm if this is still the case and why, or if the manual is outdated? (v.5.6)
I have just received my newly purchased WXC250/500's, and was ready to deploy the CMS system before I noticed this.. will set me back a while if I need to get a dedicated machine for this. :/
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07-02-2008 08:37 AM
I work for a Juniper reseller and here is what I know: While it is correct that Juniper has not supported CMS running this way - it will indeed run just fine under that scenario. The issue that you would have would be if you ran into problems with it and reached out to support. Based on my experience with JTAC I think they would still support you but they could push back if you had a really intractable issue and say you need to move CMS to a stand-alone box.
07-02-2008 08:57 AM
It has been noted that when CMS is installed on "well know virtual machine software" images there have been problems with time synchronisation. Time synchronisation is vital for any management system and of course CMS is no exception. The issue comes from the fact that the well known virtual machine software has trouble getting the clock source timing correct from the host machine; as a result this can throw off the log timing and have many knock on effects. Our developers cannot resolve an issue with another vendor’s software, hence the reason for the apparently draconian statement.
On a more positive note, a number of customers have successfully deployed CMS on a virtual machine image without issue. Kevin is correct in regards to his comment about TAC, they are a flexible and helpful bunch and I feel sure they will make every effort to support you, however, if you encounter a time synchronisation issue or something related then the recommendation will almost certainly be to use a dedicated device. I hope this helps.
07-03-2008 02:26 AM
One of the primary functions of the CMS system is to provide visibility of your WX network in order that you can produce reports from the data gathered from these devices. If there is inconstancy between the time reported by the remote WX device and the time on the local CMS station then this could potentially cause flaws in the accuracy of the reporting. How timing issues may effect other more fundamental elements of CMS is outside of my scope of knowledge of the software architecture. Ideally you would use NTP throughout a network to ensure time synchronisation, but I understand even with NTP configured the time may go out of phase on a VM CMS.
Essentially what this comes down to is risk. Officially the VM deployment of CMS is not supported. It is important to take into account the implications of that statement. If it is not supported, then it also has not been through the weeks of rigorous QA study. Yes, JTAC will likely support your deployment as they would any other CMS system, but when it comes to escalation of any unexpected issues then naturally focus will be pulled onto the potential of the VM aspect is having a negative effect.
07-23-2008 02:28 AM
Both of my client has their CMS installed on a VM and both of them are working fine. One is using the full app to do reporting and auto deployment of about 150 remote devices. We have seen the time sync problem but they just keep there eye on it.
Hope you find joy