Storage Musings

Storage- Wachstum ist ja bekanntlich so eine Sache und die Hersteller helfen einem so gerne aus; Üblicherweise mit eine großen Kiste für Kleinteile einschließlich Lizenz und Service- Erweiterung. Da wirft man dann also gerne für 1.5 Jahre Restlaufzeit das Budget der ursprünglichen Investition noch einmal hinterher – weil man den Platz ja dringend braucht.

Dank nach wie vor missverstandenem Monitoring, das oft nur Ereignisse und nicht Kapazitäten und Entwicklungen anmeldet, ereilt einen solch Ungemach nach Murphy immer kurzfristig am denkbar ungünstigsten Zeitpunkt.

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VMWare Player caveats – Bridging broken

Ein weiteres Glanzstück aus der Virtualisierungs- Schatztruhe. Tagesaktueller VMWare Player – unter Windows und die Installation eines vanilla- Debian Linux.

Schnell durch geclickt und die Netzwerkkarte auf default NAT (Network Address Translation) gelassen. Die virtuelle Maschine startet, erhält per DHCP ihre Adresse und alles bestens. Die Anwendung wird installiert getestet und der Entschluss fällt das System für die Produktion vor zu bereiten.

Feste IP Adresse aus dem regulären Adresssegment vergeben und die VM herunter gefahren – Das Interface im VMWare Player von NAT auf Bridging umgestellt und das System wieder hoch gefahren.

Zunächst alles bestens. Weitere Updates aus dem Internet nach gezogen und an nichts böses gedacht, da möchte ich mit dem lokalen Webbrowser auf das Webinterface meiner Anwendung in der virtuellen Maschine zugreifen – nichts geht.

….

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Musings on Software Defined Networking – SDN

Mal wieder etwas technisches: SDN – Softare Defined Networking mausert sich ja zum nächsten Hype – mit welchem Recht auch immer – und wie bei jedem Hype Thema springen die üblichen Verdächtigen zügig auf. Die Sprungrate hat dabei 2013 drastisch zugenommen – ob begründet oder unbegründet sei mal dahin gestellt.

Aufspringen bedeutet dabei ja gerne, dass man die Technologie, die man ohnehin schon im Haus hat etwas erweitert und dann seine eigene Deutung definiert, die einen natürlich zum gefragtesten Anbieter in dem Segment macht.

Nachdem VMWare als der Marktführer im Bereich Virtualisierung hier mit der Nicira Aquise hier früh 2012 den Reigen eröffnet hat lohnt sich ein genauerer Blick auf die Szenarien und Aufgabenstellungen, sowie den Status-Quo:

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VMWorld 2012 Musings

Mann geht ja auf Kongresse um zu lernen, Neuigkeiten und Ankündigungen mit zu nehmen und nicht zuletzt um mit dem guten Gefühl nach Hause zu fahren, dass man mit seinen Einschätzungen richtig liegt und insgesamt auf “einem guten Weg” ist.

Die diesjährige VMWorld ist da keine Ausnahme. Mit dem Unterschied, dass zwischenzeitlich tatsächlich eine Große Veränderung statt findet: Die Cloud kriegt gestalt und die vielen offenen Punkte, welche die Zweifler noch immer nähren sind aufgelistet, adressiert und wenn man mutig genug ist, auch gelöst.

Mir gefällt “elastic computing” als Begriff  eigentlich viel besser als Cloud, weil er nicht so nebulös daher kommt. Dabei machen drei Dinge eine funktionierende Umgebung aus.

* virtuelle Compute Ressourcen – Hypervisor auf “Blech”
* virtuelle Storage Ressourcen
* virtuelle Netzwerk Ressourcen

Die Virtualisierung aller drei Bereiche ermöglicht erst die agile – elastische Software-basierende Bereitstellung von Cloudsystemen. Und das unter der Prämisse, dass die Steuerung aus einem homogenen ganzheitlichen Managementsystem rollenbasierend – profilbasierend und Mandanten-fähig erfolgt. Letzeres übrigens auch für private Clouds, da verschiedene Abteilungen Mandanten-Züge haben.

Erkenntniss des Tages: Dass es ohne das vereinheitlichte Management vorraussichtlich nie rund laufen wird.

UCS Caveats: Uplinking the VIC

The VIC virtual interface card allows within the UCS universe to dynamically create up to 256 VIF – Virtual Interfaces which dynamically bind to a virtual machine within a major hypervisor (e.g. VMWare vSphere, HyperV should be supported soon).

The VIC therefore is bypassed by the virtual switching layer within the hypervisor and provides a reasonable I/O performance advantage compared to classical virtual switching concepts. Basically a “virtual switch” module within the network framework of the hypervisor binds the pre-generated logical PCI devices to a dedicated driver within the virtual machine.

Given a proper integration the so generated virtual interface shows up within the UCS-Manager running on the Nexus based Interconnect Fabric as a classical switch-port and can be managed by the network staff accordingly.

Reading the details in the white papers, the driver component within the virtual machines supports only a limited number on interfaces, in cases as limited as eleven interfaces on one hypervisor. Due to the adapter pinning that does not only cover the general network interfaces, the number of VIFs grows with the factor of additional uplinks. The biggest number I am aware of right now is 56 interfaces with four uplinks from a FEX module. Given the two interfaces of the adapter card this comes close to the 128 advertised VIFs but you need to run Linux within the VMs and you need that many uplinks.

DCUCI: Datacenter Unified Computing Implementation

This week I visited the DCUCI training. The best class I had in a reasonable while. There could have been more labs and the marketing coverage – high and wide introduction was much to much considering the fact that there were two four hour eLearning-sessions upfront which covered this stuff more accurate.

Besides this annoying waste of valuable labtime it was a really great introduction into the Unified Computing System world of CISCO. Although it was not feasible to introduce the UCS preparation and uplink configuration part, covered in an appendix, everything else was covered fair. Introducing the pool concepts, updating templates for ports – interfaces, policies and in the server profile it gave a complete introduction into the hows and whens, even the caveats of the CISCO interpretation of stateless servers.

Even the connection and distributed switching integration into VMWare vSphere with the Nexus 1000v as well as the VM-FEX approach was discussed. The labs cover preferably the Nexus 1000v but due to our smart trainer we implemented the VM-FEX approach as well.

Down this road we found a lot of caveats which never have been covered in the technical deep dive classes offered from CISCO for end customers. I was very happy to hear this class, so we may judge better which way to go. In the long run the HP Virtual Connect Flex Fabric approach is not that clumsy as it looks within a superficial comparison to CISCO UCS. Honoring the caveats, the CISCO approach has to be well designed and even more carefully maintained that the HP one. Details will follow.

Blade New World

Most computer vendors flood the marketplace with more or less sophisticated blade solutions. Remark: Blade solutions well differentiated from blade servers.

So here some musings on blades and why I tend to differentiate between basic blade servers and the more sophisticated approach.

Basic blade concepts primarily convince, considering all the same aspects:

  • Optimized footprint aka rackspace
  • Reduced cabeling
  • Energy efficiency
  • Virtualized installation media
  • Cooling efficiency
  • Central management and maintenance
  • Easy hardware deployment and service

To whatever extend the different breeds address the different issues, these primarily are seem to be the supperficial quality criteria and argued in many decission processes, missing the core scope of the discussion. These topics are covered in the mainstream publications and are measured as the grade of quality of the “solution”.

From my point of view this is completely out of scope.

The real value of blades is interconnect virtualisation together with the so called “stateless server” approach. No surprise that many vendors try to keep the discussion on the less important facts, since according to my labs and evaluations only three major vendors even understood the issue. Depending on their legacy obligations they have more or less radical approaches to reach the goal.

The goal is to generate a server personality, its identity in terms of technical aspects, dynamically by application of a so called service- or server- profile. This profile contains the different aspects of the individual server identity such as e.g.:

  • BIOS version
  • Other firmware version, e.g. HBA or NIC
  • WWNs for port and node
  • MAC addresses
  • Server UUID
  • Interface assignements
  • Priorities for QoS and power settings

Accroding to these profiles and derived from pools of IDs, MACs, WWNs the servers identity is generated dynamically and assigned during a so called provisioning phase. Then the blade server is available for installation.

This approach allows to “on the fly” generate a server personality, that serves dedicated needs as for instance an VMWare vSphere server or an database server. Furthermore if more servers from the same type are needed the profiles my be cloned or derived from ma template so that new rollouts are quick and easy. In case of failiure or desaster recovery the profiles may even roam to other, not yet personalized servers and asuming a boot from SAN or boot from iSCSI scenario failed servers are back in minutes, transarent to even hardware based licensing issues.

Derived from specially the need for flexible interconnect assignment the classical approach of dedicated Ethernet or Fibrechannel switch modules in a blade infrastructure is of no further use any more. The classical approach needs dedicated interconnects at dedicated blade positions which is exactly the limitation a service profile wants to overcome.

With converged infrastructure, the support of FCoE and data center bridging as well as the according so called converged network adapters, thi limitation has been overcome on the interconnect side. Here the interconnect is configured in an appropriate way to cover the server side settings and assigns dynamically different NIC and HBA configurations to the single blade. Even more the connections may apply QoS or bandwith reservation settings and implment high connection availability in a simplyfied manner.

Based on that far advanced and very modern hardware operation concepts are possible. Only blade concepts, that support the full range of this essentially decoupling from hardware and service role, deserve the name “solution”. Anything else is “me too”.

Some posts on howtos from my previous evaluation and installation projects will follow. Some readers may remember my old blogg 😉