Clouds, Networking and Technology

Assumptions : You are using ML2 plugin configured to use Vlans If you try to create a network for a tenant and it fails with the following error: Error: Failed to create network "Test": 503-{u'NeutronError': {u'message': u'Unable to create the network. No tenant network is available for allocation.', u'type': u'NoNetworkAvailable', u'detail': u''}} The problem can be due to missing configuration in the below files: In /etc/neutron/plugins/ml2/ml2_conf.ini network_vlan_ranges =physnet1:1000:2999 (1000:2999 is the Vlan range allocation) In /etc/neutron/plugins/openvswitch/ovs_neutron_plugin.ini bridge_mappings = physnet1:br-eth1 (in OVS we map the physical network to the OVS bridge) Note You should have created a bridge br-eth1 manually and mapped it to a port ovs-vsctl add-br br-eth1 ovs-vsctl add-port br-eth1 eth1 Once configuration is done, restart the neutron ovs agent on the compute node(s): ...

Pre-requisites CentOS 6.5 (or above) installed on a system with Openstack recommended specs Basic Network Configured and working. If you have used CentOS minimal version then you will need to configure the network manually. You can refer to the steps required here Installation yum update -y  Go to IceHouse Repo and copy the link to the latest  *****.noarch.rpm. As of December 2014, the latest rpm is : rdo-release-icehouse-4.noarch.rpm yum install -y https://repos.fedorapeople.org/repos/openstack/openstack-icehouse/**latest**.noarch.rpm yum install openstack-packstack Generate an answer file and configure it as per your requirements packstack --gen-answer-file *filename* Trigger installation using the generated answer file packstack --answer-file *filename*

When a system is installed with CentOS 6 minimal version, it's network is not configured initially and has to be manually taken care of. There are two ways of going about this: DHCP  vi /etc/sysconfig/network-scripts/ifcfg-eth0 ONBOOT = yes NM_CONTROLLED = no BOOTPROTO = dhcp  vi /etc/sysconfig/network [Hostname is needed to be specified for DHCP to work] NETWORKING = yes HOSTNAME =  vi /etc/resolv.conf [Optional] search [ex: lab1.mycompany.com finance.mycompany.net  abc.mycmp.com] nameserver Once all the above steps are done, restart the networking service: /etc/init.d/network restart [For troubleshooting] You can also consider using "dhclient eth0" to obtain an ip address for eth0 from dhcp server. Static IP Address vi /etc/sysconfig/network-scripts/ifcfg-eth0 ONBOOT = yes NM_CONTROLLED = no BOOTPROTO = none IPADDR = NETMASK = [for a /24 network it will be 255.255.255.0] GATEWAY = [Optional]  USERCTL = yes/no [Opt...

VirtualBox Guest Additions helps improve a VM's performance and usability. The biggest plus I see going for it is the dynamic screen resizing of the guest window. If you are using a supported OS with a GUI, installing the guest additions is as simple as clicking on the menu "Devices --> Insert Guest Additions CD Image" and the installation follows. On an OS without GUI, generally the server versions, you will have to do the following operations from the CLI to install the guest additions:

Django is a python web development framework that helps in rapid application development. Once you are comfortable with the basics, developing UI applications with Django framework is a breeze and helps the developers to focus on the problem at hand rather than on UI nitty gritty. An understanding of this framework is a must in order to develop applications for Openstack Horizon module. In this article, I will list out the steps that need to be carried out to get a Django setup ready for the initial learning phase. At the end of this article, I have included all the links that I have followed when I initially learnt this framework.

[This is meant for my reference, so data will be from random areas] Setting a Port to trunk all set interfaces ge-0/0/45 unit 0 family ethernet-switching port-mode trunk set interfaces ge-0/0/45 unit 0 family ethernet-switching vlan members all Save/Restore Snapshots [edit] save file-name load file-name Logging out a user : If you want to log out a stale session root@srx> edit Entering configuration mode Users currently editing the configuration:   root terminal u0 (pid 94668) on since 2014-12-01 10:52:51 UTC, idle 1w2d 18:02 [edit] root@srx# run request system logout pid 94668 [A much cleaner way is to set the ssh timeout for the user] Find all users logged onto a device [edit] Status

Once in a while, on a new setup, when you try to spawn a VM on Openstack and it may fail with the error :  No Suitable Host Found, it points to the fact the the Nova Scheduler failed to filter out a host to spawn the VM on. [The following trouble shooting is related to my setup. There are a lot of other factors that may lead to this error. So google a bit and check them in addition. This article can help you in figuring out the way to do troubleshooting.] A quick look at /var/log/nova/scheduler.log and compute.log shows an error: NovaException: Unexpected vif_type=binding_failed Filter RetryFilter returned 0 hosts This points to the fact that something is wrong with the Neutron setup. So a quick look into the neutron logs show the following:

I have recently come across a great book on JTA @ http://www.infoq.com/minibooks/JTDS Happy reading....

I found an excellent blog with instructions on how to use SL4J with various logging frameworks @ http://java.dzone.com/articles/how-configure-slf4j-different

Javascript has an inbuilt library object to handle json data. In order to convert a json string to an object, you can use the following method call: var obj = JSON.parse("jsonString")  for the other way around : var jsonString = JSON.stringify(obj); Check out the site  http://jsonlint.com/. It's very useful to format json strings.

I have come across a free online book with gives an excellent** introduction to D3js. You can access it @ http://chimera.labs.oreilly.com/books/1230000000345/index.html You can buy the book @ http://chimera.labs.oreilly.com/books/1230000000345