Agile testbed
Warning: some elements of this page are severely outdated!
Agile testbed
The state of the testbed is going to change, as we are planning to integrate several more machines and change the overall setup of systems and services. See Testbed_Update_Plan.
The Agile testbed is a setup of easy-come easy-go virtual machines for quickly trying out new and experimental software.
It is used in the context of the P4 activity of the VL-e project, the SA3 activity in the EGEE III project and Application support in the BiG Grid project.
The test bed is hosted at the Nikhef data processing facility, and managed by Dennis van Dok, Jan Just Keijser, Mischa Sallé and Willem van Engen.
A new setup using OpenNebula is work in progress.
Hardware
The testbed currently consists of four physical machines: bleek, toom, kudde and span.
| name | type | #cores | mem | OS | disk | remarks |
|---|---|---|---|---|---|---|
| bleek | Intel 5150 @ 2.66GHz | 4 | 8GB | CentOS4-64 | software raid1 2×500GB disks | High Availability, dual power supply |
| toom | Intel E5440 @ 2.83GHz | 8 | 16GB | CentOS5-64 | Hardware raid1 2×715GB disks | |
| kudde | Intel E5440 @ 2.83GHz | 8 | 16GB | CentOS5-64 | Hardware raid1 2×715GB disks | |
| span | Intel E5440 @ 2.83GHz | 8 | 24GB | CentOS5-64 | Hardware raid10 on 4×470GB disks (950GB net) | DHCP,DNS,NFS,LDAP |
Network
The network between these machines is a bit particular: They all live in the same VLAN (194.171.96.16/28) but they all have an extra alias interface in the 10.198.0.0/16 range. The Xen DomUs on each of the Xen machines that live in that address range are given connectivity to the other DomUs in the same VLAN without using NAT, and connectivity to the outside with SNAT. Here's an example of the iptables on span:
Chain POSTROUTING (policy ACCEPT 58M packets, 3693M bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- any any 10.198.0.0/16 194.171.96.16/28
436 63986 ACCEPT all -- any any 10.198.0.0/16 10.198.0.0/16
1 190 SNAT all -- any any 10.198.0.0/16 anywhere to:194.171.96.28
So all traffic from a DomU on span will appear to have come from span to the outside.
Note that DomUs that have interfaces in the public address range do not need SNAT at all, they simply connect to the hosts xen bridge.
There is a separate network attached to each machine to allow IPMI management and Serial-Over-Lan.
Software Installation
The central machine in the network is span, it runs
- dnsmasq for DNS and DHCP based on /etc/hosts and /etc/ethers
- NFS server for the home directories and ssh and pem host keys
The other Xen machines, toom and kudde, run Xen 3.1. On these machines the creation and destruction of virtual machines is best left to the generate-machine and destroy-machine scripts, part of the nl.vl-e.poc.ctb.mktestbed software package.
Operational procedures
The testbed is not too tightly managed, but here's an attempt to keep our sanity.
Server certificates
Host or server SSL certificates for volatile machines in the testbed are kept on span.nikhef.nl:/var/local/hostkeys. The FQDN of the host determines which CA should be used:
- for *.nikhef.nl, the TERENA eScience SSL CA should be used,
- for *.testbed, the testbed CA should be used.
Generating certificate requests for the TERENA eScience SSL CA
- Go to bleek.nikhef.nl:/var/local/hostkeys/pem/
- Generate a new request by running ../make-terena-req.sh hostname. This will create a directory for the hostname with the key and request in it.
- Send the resulting newrequest.csr file to the local registrar (Paul or Elly).
- When the certificate file comes back, install it in /var/local/hostkeys/pem/hostname/.
Requesting certificates from the testbed CA
Kindly ask Dennis. The CA key is on his eToken, which means no one else can generate host certificates. Some time in the future this will be replaced by a simple CA setup on the testbed itself.
Logging of changes
All changes need to be communicated by e-mail to CTB-changelog@nikhef.nl.
(This replaces the earlier CTB Changelog.)
adding a new machine
preparations on bleek
- edit
/etc/hosts /etc/ethers
to add the new machine, and hardware address.
- Restart dnsmasq
/etc/init.d/dnsmasq restart
- on span.nikhef.nl, run
/usr/local/bin/keygen <hostname>
to pre-generate ssh keys.
- on span, run
/var/local/hostkeys/generate-knownhosts.sh
- on all machines, do
cp /var/local/hostkeys/ssh_known_hosts /etc/ssh/ssh_known_hosts
- (optional) generate or request an X509 host certificate. For local machines in the .testbed domain, Dutchgrid certificates won't be issued, but a testbed-wide CA is in use, ask Dennis. The certificate and key are stored in
/var/local/hostkeys/pem/<hostname>/hostcert.pem /var/local/hostkeys/pem/<hostname>/hostkey.pem
- place a 'firstboot' script on span in
/var/local/xen/firstboot/<hostname>
(it will be downloaded and run the first time after installation of the machine.)
starting the installation on the dom0
The old generate-machine script still works for Xen Dom0. For blade13 and blade14 (and other libvirt machines) this script sort of works:
virt-install --name my-new-machine.testbed --ram 1024 --disk pool=vmachines,size=10 \
--network bridge=br0,mac=52:54:00:48:22:32 --os-type linux --os-variant rhel5.4 \
--location http://spiegel.nikhef.nl/mirror/centos/5/os/x86_64 \
--extra ks=http://bleek.nikhef.nl/mktestbed/kickstart/centos5-kvm.ks
Take into account that the mac address is what is configured in /etc/ethers on bleek.nikhef.nl; the disk pool points to the Compellent Fiber Channel pool.
A debian installation is similar, but uses preseeding instead of kickstart. The preseed configuration is on bleek.
virt-install --name debian-builder.testbed --ram 1024 --disk pool=vmachines,size=10 \
--network bridge=br0,mac=52:54:00:fc:18:dd --os-type linux --os-variant debiansqueeze \
--location http://ftp.nl.debian.org/debian/dists/squeeze/main/installer-amd64/ \
--extra 'auto=true priority=critical url=http://bleek.testbed/d-i/squeeze/preseed.cfg'
A few notes:
- The network autoconfiguration seems to happen too soon; the host bridge configuration doesn't pass the DHCP packets for a while after creating the domain which systematically causes the Debian installer to complain. Fortunately the configuration can be retried from the menu. The second time around the configuration is ok.
- Alternative installation kickstart files are available; e.g. http://bleek.nikhef.nl/mktestbed/kickstart/centos6-64-kvm.ks for CentOS 6.
- With Debian preseeding, this may be automated by either setting d-i netcfg/dhcp_options select Retry network autoconfiguration or d-i netcfg/dchp_timeout string 60.
- Sometimes, a storage device is re-used (especially when recreating a domain after removing it and the associated storage). The re-use may cause the partitioner to see an existing LVM definition and fail, complaining that the partition already exists; you can re-use an existing LVM volume by using the argument: --disk vol=vmachines/blah.
Automatic configuration of machines
The default kickstart scripts for testbed VMs will download a 'firstboot' script at the end of the install cycle, based on the name they've been given by DHCP. Look in span.nikhef.nl:/usr/local/mktestbed/firstboot for the files that are used, but be aware that these are managed with git (gitosis on span).
Configuration of LDAP authentication
Fedora Core 14
The machine fc14.testbed is configured for LDAP authn against ldap.nikhef.nl. Some notes:
- /etc/nslcd.conf:
uri ldaps://ldap.nikhef.nl ldaps://hooimijt.nikhef.nl base dc=farmnet,dc=nikhef,dc=nl ssl on tls_cacertdir /etc/openldap/cacerts
- /etc/openldap/cacerts is symlinked to /etc/grid-security/certificates.
Debian 'Squeeze'
Debian is a bit different; the nslcd daemon is linked against GnuTLS instead of OpenSSL. Due to a bug (so it would seem) one cannot simply point to a directory of certificates. Debian provides a script to collect all the certificates in one big file. Here is the short short procedure:
mkdir /usr/share/ca-certificates/igtf for i in /etc/grid-security/certificates/*.0 ; do ln -s $i /usr/share/ca-certificates/igtf/`basename $i`.crt; done update-ca-certificates
The file /etc/nsswitch.conf needs to include these lines to use ldap:
passwd: compat ldap group: compat ldap
This file can be used in /etc/nslcd.conf:
uid nslcd gid nslcd base dc=farmnet,dc=nikhef,dc=nl ldap_version 3 ssl on uri ldaps://ldap.nikhef.nl ldaps://hooimijt.nikhef.nl tls_cacertfile /etc/ssl/certs/ca-certificates.crt timelimit 120 bind_timelimit 120 nss_initgroups_ignoreusers root
The libpam-ldap package needs to be installed as well, with the following in /etc/pam_ldap.conf
base dc=farmnet,dc=nikhef,dc=nl uri ldaps://ldap.nikhef.nl/ ldaps://hooimijt.nikhef.nl/ ldap_version 3 pam_password md5 ssl on tls_cacertfile /etc/ssl/certs/ca-certificates.crt
At least this seems to work.
