I'm trying to workaround a DHCP issue by configuring my guest VM to use DHCP (to avoid having to configure it manually with a static IP) but defining a static IP in the XML.
This would enable setting an IP upon creation while not requiring configuring the virtual machines operating system to a static IP (making it sort of "independent").
I should point out:
Guests are Windows/Linux mixed
Must use a bridge setup (not NAT)
Is this a reasonable solution? any recommendations to the actual XML markup of the guest?
When saying static ip configuration instead of DHCP, it's not a libvirt thing but a configuration of guest OS. refer to this maillist for example.
So you can make it via a custom DHCP server that listens on your bridge network instead of default NAT. it only assigns specific ips to specific mac addresses. It's very easy to make it via dnsmasq.
If you do want to exclude any DHCP broadcast in your bridge network, think about bootstrap processes inside your guest OS. The config drive is a good choice where it allows you creating a disk file and attach to the VM, then the cloud-init daemon on guest OS will pick it up to replace network configuration. But it's just too many if you just want static ips.
Related
I have a local network with several PCs and specialized controllers on it. These specialized controllers must be configured with static IP addresses and do not have DHCP capabilities.
I was asked to put together a list of the device hostnames and IP addresses. It's easy to figure out the IP address of each device, however, I'm struggling to find out the host name for these specialized controllers. If it were a Windows PC, I would simply navigate some menus to find the host name.
I'm confused about how the host name is configured for network devices in general. For Windows PCs, it seems like the PC itself determines its own host name. When it joins a network, it simply broadcasts its host name to a DNS server and the DNS server remembers it. For devices that are not DHCP, it seems like I would need to manually go to a DNS server and enter the host name for the specific IP address.
So what exaclty determines the host name? The device itself or a network admin?
This more of networking question and belongs to ServerFault - you will get your answer faster there.
If it were a Windows PC, I would simply navigate some menus to find
the host name.
What kind of system is there if there is no Windows? Linux, *BSD, AIX, other? I'll answer for Linux for now.
So what exactly determines the host name? The device itself or a
network admin?
This depends on your configuration in Linux check - /etc/nsswitch.conf
e.g.
hosts: files dns
Which defines that the hostname will be defined by /etc/hosts and if it is not found there it will check DNS next.
If hosts file, the local resolution, contains the pair ip <-> name it is used. If the DNS takes precedence and it contains the pair it is taken from there. As shown above, it can contain both at once in defined order, then the resolution is done in that order.
By the way, DHCP server can give you static IP addresses based on your MAC address so your controllers will have always the same IP address, if same network card is used. It is way easier to manage than configure all servers manually.
I have installed at work SAP Hana Express Edition 2.0 in my laptop. It runs on VMware/Suse. I also set up a static IP address so I don't have to change the client connections. This works fine when I'm at work.
I added the following to hosts file:
192.168.1.85 hxehost
Problem is that when I take my laptop somewhere else all my client connections time out. I checked the IP address in Suse and it's the one I assigned. How to fix this problem?
If I disconnect the laptop from the Internet, I get the following error:
JDBC: Cannot connect to jdbc:sap://192.168.1.85:39013/ [Cannot connect to
host 192.168.1.85:39013 [No route to host: connect],
This is my setup:
How you connect to the virtual machine's IP ports depends on the setup chosen for the VM networking.
The address 192.168.1.85 is part of the 192.168.1.x network, which is very popular for home-router setup and small LANs. It's very likely that your laptop is part of such a network, when not at work. So when you ping the address the laptop uses the network interface that is linked to this network (e.g. your wifi adapter) to look for the host with IP 192.168.1.85. Whoever host currently got the 85 in your network, it's likely not your virtual machine.
One easy way to avoid this is to setup the virtual machine with host-only network. For that you have to configure the network adapter in VMware (or whatever hypervisor you use) to use the host-only network and assign an IP address in a different subnet e.g. in 192.168.5.x. For the HANA client software on your computer, the address to use would, of course, be 192.168.5.85 but it would be stable across all networks your laptop may log into.
I'm looking to set up a few virtual hosts for different domains for a few friends, and want to know if one virtual host can access files from another host, whether it be via PHP or any other option or if it's totally isolated, so any scripts they can run would only affect their area.
An Apache "virtual host" is just a mapping of a hostname (or ip address or port) to a particular set of configuration directives. There is no "containment" or isolation implied by this; everything is still running on the same host.
If you want to actually isolate applications, consider investigating container technology like Docker (or a virtual machine solution), with a front-end proxy directing traffic as necessary to the appropriate backend.
I am wondering if there is a way to setup a static IP address to a virtual machine (VirtualBox) hosted on a GCE VM instance (as a VM host).
I want to run two VirtualBox VMs on my GCE VM instance and I want to access them publicly.
Yes, you can do this, but you should also consider whether you want the additional overhead of running one virtual machine (VirtualBox) inside of another virtual machine (GCE VM). Running directly on GCE VMs would be more efficient and you can easily create/destroy/control these VMs via Google Cloud Platform APIs.
In addition, if you are already using an automation framework for your VirtualBox VMs such as Vagrant, note that Vagrant natively supports GCE VMs, so with a few changes to your configuration, you can use Vagrant to create/modify/connect/destroy your GCE VMs as easily as you would local VirtualBox VMs.
As an alternative to static external IPs, consider also using a domain name mapping to ephemeral external IP(s) of your instance(s). You can use Google Cloud DNS to manage your DNS mappings.
For more info on static external IPs, see the docs:
Static external IP addresses
If you need a static external IP address that is assigned to your project and persists until you explicitly release it, you can reserve a new static external IP address or promote an ephemeral external IP address to a static external IP address. Use gcloud compute with the addresses create command or make a PUT request to the appropriate regional Addresses collection to reserve a static external IP address.
Static external IP addresses assigned to instances are a regional resource and you must select the region where the IP address will belong to when you create the address.
[...]
Restrictions
Static external IP addresses can only be used by one resource at a time. You cannot assign a static external IP address to multiple resources.
There is no way to tell whether an IP address is static or ephemeral after it has been assigned to a resource, except to compare the IP address against the list of static external IP addresses reserved to that project. Use the addresses list sub-command to see a list of static external IP addresses available to the project.
Note that static external IPs also come with some cost:
IP address pricing
Type Price/Hour
Static IP address (assigned but unused) $0.01
Static IP address (assigned and in use) No charge
Ephemeral IP address (attached to instance or forwarding rule) No charge
I solved that issue to in 2 steps:
First delete the current possible ephimeral ip configuration:
gcloud compute instances delete-access-config <instance> --access-config-name "External NAT"
Where <instance> is the name of the instance you want to update, and External NAT is the name of the configuration, which probably has that value because of its the default one. And you can check it running this:
gcloud compute instances describe --zone=us-west1-a
And add the static one
If you want to bind an static address, probably to bind it to a DNS address, execute something like this
gcloud compute instances add-access-config <instance> --access-config-name="External NAT" --address=xxx.xxx.xxx.xxx
Remember to always append the --zone to any gcloud command to avoid any ambiguity. You can get the address from the valid addresses configuration you have in your project, which you can be gotten like this:
gcloud compute addresses list
Dont use the NAME but the ADDRESS. You should pick an address in the same zone of your instance. When the address be attached you will see that in the STATUS field of the last query it will say IN USE.
Et voila!
does anybody know an API that allows to send and receive data to/from a VMWare guest system without using an IP network?
I have to communicate with a program inside a VMWare guest but the guest is not allowed to have an IP network. As file transfers into the VM via Drag&Drop are possible I assume that there is an API - I just need to know if this API is open to 3rd party programmers or if it is only available fro the VMWare Player itself.
Sure, you can access those with the VIX API.
More specificely, the Drag&Drop is implemented with following functions:
VixVM_CopyFileFromGuestToHost
VixVM_CopyFileFromHostoGuest
Basically all VixVM functions may be relevant for your tasks. They are all documented in the official VIX API reference.
It turns out that there is a solution for my problem:
Virtual Serial Port
VM-Ware allows to create virtual serial ports for the guest that are connected on host side to a named pipe.
I therefore created two helper programs, one on host side which listens on a TCP port and a specific named pipe and transfers all the incoming data between them.
A second helper program runs in the guest VM and does the same between the serial port and the TCP port I want to access.
The only draw-back is that the serial speed is limited to 128kBit/sec. May be that can be increased by using multiple virtual serial ports...
Virtual Machine Communication Interface (VMCI)
Using VMCI there is an API for creating a shared memory region that is accessible from both hast and guest system.