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Copyright 2010-2017, Gianrico Fichera
Last update: 9
Feb 2017
Previous update: March 15, 2010
What is IOS-XR
IOS-XR is a Cisco operating system running in the Cisco XR12000, Cisco CRS-X, Cisco ASR and Cisco NCS series. Before the release 6.0 it was based on the QNX neutrino RTOS microkernel. The CRS-X (introduced in 2004) system adopt the Intel Xeon processor. The ASR use the Cisco Flow processor, with 40 cores and 4 threads capacity for core (40x4 packet processing at once). From the release 6.0 Cisco use Openembedded linux.
Cisco
32 bit QNX neutrino
1.) IOS-XR is a microkernel operating system type architecture.
Operating systems can be either with a monolithic kernel or with microkernel. In the first case, the operating system processes run in the space reserved for the kernel space while the user processes run in a separate space reserved for them (user space). In microkernel only a minimal core of the operating system runs in kernel space. All other processes runs in user space. In this way, only a microkernel crash could lock the system, but this 'may' be avoided by carefully designing a limited portion of code. All other processes (such as device drivers and protocol stacks), run in user space and thus can be controlled individually. A crash of a process does not block the system. The disadvantage of microkernel is the need for a greater number of memory and processor resources. In fact, the communication between separate processes is inevitably slower than in a monolithic kernel. User space processes should make library calls to the kernel for getting hardware access, because only kernelspace processes can get hardware access directly. The QNX microkernel is very small (I read about 10KB! you can see details here)
Cisco IOS isn't a microkernel OS. Single process crash can take down whole system. All processes share the same memory space. There isn't memory isolation.
2.) IOS-XR is a pre-emptive operating system type architecture. This means that there is a scheduler, a process running in kernel space, responsible of the division of time between processes running on your system. This process use a context-switch algorithm to save the process status and restore it later. In cooperative multitasking instead is responsibility of each process to release resources for the system to make room for other processes. It is obvious that if a process is not working properly the whole system may crash and have to be restarted. IOS is a cooperative multitasking (like the first 16bit Windows operating systems ). IOS-XR is a pre-emptive multitasking operating system (such as a Unix system or Windows 2000 for example)
3.) IOS-XR use memory protection between
processes. This means that a process is unable to access memory that
hasn't been allocated for it.
Cisco
64 bit QNX OpenEmbedded Linux (from 6.0 IOS-XR release)
http://www.cisco.com/assets/global/DK/seminarer/pdfs/XR60.pdf
YOCTO
project <--- usato da Cisco per preparare il proprio
OpenEmbedded Linux
-----------------
Virtualizzazione ----------------
Aggiornato: Febbraio 2017
CISCO
-
Cisco chiama "Open Service Containers" la funzionalita' con la
quale in un router possono essere lanciati dei container per avere
delle funzionalita' aggiuntive. Questi container possono essere sia
forniti da Cisco che creati dall'utente (per questo Open). Un
container puo' fare qualsiasi cosa ad esempio File server o DNS server
etc.);
-
Cisco utilizza sia LxC (Linux virtual Containers) che KVM nei suo
prodotti. In IOS-XR dalla versione 6.0 ho visto che si utilizza LxC.
Anche i sistemi operativi come IOS-XE dalla 3.17-16.2 (Nov. 2015)
permettono l'uso di LxC e KVM sulla serie ISR4000 (dal 4321-ISR con la
giusta DRAM e storage NIM-SSD) e ASR1000, anche CSR1000V; (Vedi
qui per i dettagli dell'hardware e su come usarlo)
- Con Cisco KVM si aspetta le macchine virtuali nel formato OVA che al
suo interno, tra gli altri, ha il file di configurazione package.yaml
Per creare le macchine, l'hardware e il resto: Clicca
qui
LINUX
-
I containers sono piu' veloci delle macchine virtuali VMWARE o KVM
perche' utlizzano gli stessi drive hardware della macchina ospite
invece di creare un layer di emulazione hardware o dello storage.
Inoltre possono copiarsi facilmente tra un sistema e l'altro (purche'
su entrambi ci sia installato LxC)
- Che differenza c'e' tra LxC e Dockers? LxC puo' lanciare conteiner
che eseguono processi multipli (anche quindi un'altro Linux) mentre
Dockers sono container che contengono un singolo processo. Cosi' per
utilizzare un wordpress in Docker crei piu' container, ad esempio uno
con PHP, uno con MySQL, uno con apache e poi li fai comunicare tra
loro. In alternativa ci sono degli altri metodi, ma Docker non nasce
per poter fare questo. Insomma LxC sembra piu' potente di Docker che
e' sembrerebbe un prodotto commerciale;
-
Installazione su CentOS 7:
(http://www.tecmint.com/install-create-run-lxc-linux-containers-on-centos/)
1)
yum install epel-release <-- ATTENZIONE SENZA QUESTA
RIGA LA SUCCESSIVA INSTALLA DOCKER!!!
yum install lxc
yum install lxc-templates
yum install debootstrap perl libvirt
systemctl enable lxc.service
systemctl start lxc.service
systemctl enable libvirtd
systemctl start libvirtd
systemctl status lxc.service
systemctl statuc libvirtd.service
2)
lxc-checkconfig
3)
I template sono qui:
ls -alh /usr/share/lxc/templates/
4)
ESTENDERE LA PARTIZIONE SWAP
Vai qui:
https://help.ubuntu.com/12.04/serverguide/lxc.html#lxc-hostsetup
LXC stores container information and (with the default backing store) root filesystems under /var/lib/lxc. Container creation templates also tend to store cached distribution information under /var/cache/lxc.
If you wish to use another filesystem than /var, you can mount a filesystem which has more space into those locations. If you have a disk dedicated for this, you can simply mount it at /var/lib/lxc. If you'd like to use another location, like /srv, you can bind mount it or use a symbolic link. For instance, if /srv is a large mounted filesystem, create and symlink two directories:
sudo mkdir /srv/lxclib /srv/lxccache
sudo rm -rf /var/lib/lxc /var/cache/lxc
sudo ln -s /srv/lxclib /var/lib/lxc
sudo ln -s /srv/lxccache /var/cache/lxc
or, using bind mounts:
sudo mkdir /srv/lxclib /srv/lxccache
sudo sed -i '$a \
/srv/lxclib /var/lib/lxc none defaults,bind 0 0 \
/srv/lxccache /var/cache/lxc none defaults,bind 0 0' /etc/fstab
sudo mount -a
Prima di creare un container potrebbe essere necessario effettuare delle
operazioni. Se ad esempio su Debian si vuole installare un container
Ubuntu si deve creare un link symbolico in /usr/bin. Per i dettagli vedi
qui
Se si vuole creare un container debian e' facile:
Lancia il container in background:
Altri
comandi:
lxc-ls to
list your containers
lxc-info to
obtain information about a running/stopped container.
lxc-ls --active
In order to login to the container console issue the lxc-console command against a running container name
And finally, all created containers reside in /var/lib/lxc/
Create the Container archive on a Linux
Server.
• Copy the archive file to /misc/app_host.
• Unarchive in a rootfs directory.
• Create XML file specifying LXC
parameters.
• Run virsh command.
36
Routing Processor
64-bit Host OS
Control
Plane
Admin Plane
Third
Party
virsh –c lxc+tcp://10.11.12.15:16509 create
https://www.cisco.com/c/dam/en/us/products/collateral/routers/asr-1000-series-aggregation-services-routers/q-and-a-c67-737653.pdf
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