When running a ReadyMedia (aka MiniDLNA, but it could be the case for any application using multicast) server on a bridged interface (like br0), multicast_snooping must be disabled on the bridge:
echo 0 > /sys/devices/virtual/net/br0/bridge/multicast_snooping
to make the change permanent:
echo 'net.br0.bridge.multicast_snooping=0' > /etc/sysctl.d/98-minidlna_no_snoop.conf
Running a Fedora 21, Fedora 22 or a RHEL/CentOS 7 LXC container created by the lxc-create Fedora template can result in a 100% cpu loop for the systemd-journald process.
To fix this issue you must add lxc.kmsg = 0 to the container configuration. This can be done easily for all the Fedora templates in one shot:
echo "lxc.kmsg = 0" >> /usr/share/lxc/config/fedora.common.conf
WebVirtMgr (by retspen) is a simple but great libvirt frontend written in python with Django. It currently supports only KVM as hypervisor. However libvirt can be already used to manage other hypervisors (like XEN) and it also supports LXC containers.
Using the container libvirt feature I extended WebVirtMgr, creating a fork, which adds LXC support and other minor improvements (see https://github.com/daniviga/webvirtmgr/commits/master)
LXC support currently has some limitations:
- The LXC container filesystem must be created manually (this is a libvirt limitation)
- Even the LXC domain creation isn’t supported right now (you need to create the XML and define the domain manually, virt-install can be used)
- Web remote console is under development and not yet ready (some work has been made using butterfly)
- LXC domain deletion doesn’t remove its filesystem
- Snapshotting is not supported (another libvirt limitation, it can be done manually with LVM or Btrfs)
But basic functions works well:
- Management of remote hosts (via TCP, SSH, TLS, socket)
- Start, stop, shutdown, pause
- CPU and RAM limits assignment
- Network interfaces management
- Clone (only the domain, filesystem must be copied manually)
My WebVirtMgr fork contains also some minor differences and improvements compared to the original:
- The old connections list page (with a table instead of boxes) has been kept
- It supports a very basic ACLs system (for both KVM and LXC). With this feature non-admin users can be created (using the django-admin interface) that can only have specific access to a pre-defined set of VMs/LXCs. This means that user “foo“, for example, can only start/stop/shutdown or access the remote console of the VM “my_vm“
The installation procedure remains the same as the original project.
This is the connections page backported from WebVirtMgr 4.8.7
The KVM instances view
The LXC instances view
An example of a running LXC container
An LXC domain can be cloned, and a random MAC address can be generated
An example of an LXC deletion
Instance admin interface: you can assign users
How to flash a new firmware and how to set the network remotely without rebooting.
Download the new firmware (version 1.4 as writing) from the HP website
The flashing utility SOCFLASH is available on the Aspeed website (direct link). The utility is available also for Linux both 32 and 64 bit.
Flash the new RAC firmware
$ ./socflash.sh all.1.4.bin old.1.3.bin
ASPEED SOC Flash Utility v.1.09.04
Find ASPEED Device 1a03:2000 on 3:0.0
Relacate IO Base: e800
MMIO Virtual Address: 3e18000
Static Memory Controller Information:
CS0 Flash Type is SPI
CS1 Flash Type is NOR
CS2 Flash Type is SPI
Boot CS is 2
Flash Type: SPI
[Warning] Don\'t AC OFF or Reboot System During BMC Firmware Update!!
[SOCFLASH] Flash ID : 180101
Find Flash Chip #1: SpansionS25FL128 SE64KB
Backup Flash Chip O.K.
Check Flash Chip #1 at: 440000
Setup IPMI in the OS
$ modprobe ipmi_si type=kcs ports=0xca2
$ echo "ipmi_si type=kcs ports=0xca2" > /etc/modprobe.d/ipmi.conf
Change the network settings
$ ipmitool shell
ipmitool> lan set 1 ipsrc static
ipmitool> lan set 1 ipaddr 172.16.12.238
Setting LAN IP Address to 172.16.12.238
ipmitool> lan set 1 netmask 255.255.255.0
Setting LAN Subnet Mask to 255.255.255.0
ipmitool> lan set 1 defgw ipaddr 172.16.12.10
Setting LAN Default Gateway IP to 172.16.12.10
ipmitool> mc reset warm
Sent warm reset command to MC
After upgrading my HP MicroServer with Remote Access Card from Fedora 17 to Fedora 18 (kernel-3.8.3-203.fc18) the RAC KVM console (remote and VGA) stopped to work with ‘out-of-range’ signal after:
[ 4.072580] [drm] Initialized drm 1.1.0 20060810
[ 4.104362] [drm] AST 1100 detected
[ 4.104500] [drm] dram 816000000 1 16 04000000
[ 4.104785] [TTM] Zone kernel: Available graphics memory: 2024944 kiB
[ 4.104913] [TTM] Initializing pool allocator
[ 4.105035] [TTM] Initializing DMA pool allocator
[ 10.522147] [sched_delayed] sched: RT throttling activated
The MicroServer RAC has an AST1100 video controller that currently doesn’t work very well with the Linux KMS (Kernel Mode Setting).
So, to fix this issue you need to disable the KMS for the ast module:
- Edit /etc/sysconfig/grub and at the end of the GRUB_CMDLINE_LINUX line add “ast.modeset=0 nomodeset”
GRUB_CMDLINE_LINUX="rd.md=0 rd.lvm=0 rd.dm=0 SYSFONT=latarcyrheb-sun16 rd.luks=0 KEYTABLE=it LANG=en_US.UTF-8 ast.modeset=0 nomodeset quiet"
- Update the grub2 configuration
grub2-mkconfig -o /boot/grub2/grub.cfg
- Create /etc/modprobe.d/ast.conf with
- Update the initramfs with dracut
The bug has been reported at RedHat Bugzilla bug #926064.
license: GPL and additional rights
author: Dave Airlie
vermagic: 3.8.3-203.fc18.x86_64 SMP mod_unload
parm: modeset:Disable/Enable modesetting (int)
To reduce host CPU usage with a CentOS 5 VM on KVM is important to add
to grub.conf as kernel parameter
kernel /vmlinuz-2.6.18-348.1.1.el5 ro root=LABEL=/ console=ttyS0,115200 divider=10
This will reduce the internal kernel timer from 1000 Hz to 100 Hz.
Although additional parameters are not required, the divider=10 parameter can still be used. Guests with this parameter will produce less CPU load in the host, but will use more coarse-grained timer expiration. (http://s19n.net/articles/2011/kvm_clock.html)
On MicroServer the CPU load reduce is quite visible:
For more info read http://s19n.net/articles/2011/kvm_clock.html.
- have a one-way local copy of my work address (“A”)
- do the same for my private mail address (“B”)
- make them accessible together through an easy interface
- all software must be open and free
- my own mail address is on Gmail with IMAPS access enabled
- my work mail address is accessible via a standard IMAP server
- I already have a LAMP webserver in a LXC container hosted on my MicroServer
What you need:
- Linux, of course
- an internet connection (really?)
- a great tool called OfflineIMAP (http://offlineimap.org/)
- an IMAP server, DOVECOT (http://www.dovecot.org/) in this case
How does it work?
remote IMAP server --> offlineimap --> maildir on localstorage --> local dovecot imap server --> webmail/mail client (like claws-mail http://www.claws-mail.org/)
the local maildir is created as
MAILDIR INBOX -> ACCOUNT A --> INBOX ---> SUBFOLDER 1
---> SUBFOLDER 2
MAILDIR INBOX -> ACCOUNT B --> INBOX ---> SUBFOLDER 1
---> SUBFOLDER 2
Ok, let’s go!
For more info visit MicroServer page