Towards higher availability

In this post I’ll demonstrate how easy it is to setup open virtualization system with hypervisor and management. oVirt is based on Red Hat’s Red Hat Enterprise Virtualization manager (RHEV-M) and Red Hat Enterprise Virtualization hypervisor (RHEV-H).

Some oVirt Information

oVirt is a virtualization management framework constisting of a small host image, the oVirt Node, that provides the libvirt service to host virtual machines, and a robust vm management software stack, controlled by a web-based management interface, the oVirt Server.

So lets start with installing some prerequisite packages:

[root@ovirt-manager ~]# yum install -y wget postgresql-server postgresql-contrib pgadmin3 java-1.6.0-openjdk-devel

Next we’ll add new repository for ovirt:

[root@ovirt-manager ~]# wget http://www.ovirt.org/releases/nightly/fedora/16/ovirt-engine.repo -P /etc/yum.repos.d/

Final step is to install actual ovirt-manager packages:

[root@ovirt-manager ~]# yum install -y ovirt-engine ovirt-engine-setup

Now we have all needed packages installed and we can configure manager.

[root@ovirt-manager ~]# engine-setup Welcome to oVirt Engine setup utility HTTP Port  [8080] : HTTPS Port  [8443] : Host fully qualified domain name, note that this name should be fully resolvable  [ovirt-manager.demo.local] : ovirt-manager.demo.local did not resolve into an IP address User input failed validation, do you still wish to use it? (yes|no): yes Password for Administrator (admin@internal) : Warning: Weak Password. Confirm password : Database password (required for secure authentication with the locally created database) : Warning: Weak Password. Confirm password : Organization Name for the Certificate: Demolab The default storage type you will be using  ['NFS'| 'FC'| 'ISCSI']  [NFS] : Should the installer configure NFS share on this server to be used as an ISO Domain? ['yes'| 'no']  [yes] : yes Mount point path: /install Display name for the ISO Domain: install Firewall ports need to be opened. You can let the installer configure iptables automatically overriding the current configuration. The old configuration will be backed up. Alternately you can configure the firewall later using an example iptables file found under /usr/share/ovirt-engine/conf/iptables.example Configure iptables ? ['yes'| 'no']: yes  oVirt Engine will be installed using the following configuration: ================================================================= http-port:                     8080 https-port:                    8443 host-fqdn:                     ovirt-manager.demo.local auth-pass:                     ******** db-pass:                       ******** org-name:                      Demolab default-dc-type:               NFS nfs-mp:                        /install iso-domain-name:               install override-iptables:             yes Proceed with the configuration listed above? (yes|no): yes

After this setup might take while, but in few minutes you should get output like below:

Installing: Configuring oVirt-engine...                              [ DONE ] Creating CA...                                           [ DONE ] Setting Database Security...                             [ DONE ] Creating Database...                                     [ DONE ] Updating the Default Data Center Storage Type...         [ DONE ] Editing JBoss Configuration...                           [ DONE ] Editing oVirt Engine Configuration...                    [ DONE ] Configuring the Default ISO Domain...                    [ DONE ] Configuring Firewall (iptables)...                       [ DONE ] Starting JBoss Service...                                [ DONE ]   **** Installation completed successfully ******       (Please allow oVirt Engine a few moments to start up.....)  Additional information:  * There is less than 4 GB available free memory on the Host. It is  recommended to have at least 4 GB available memory to run the RHEV Manager.  * Keystore already exists, skipped certificates creation phase  * A default ISO share has been created on this host.    If IP based access restrictions are required, please edit /install entry in /etc/exports  * The firewall has been updated, the old iptables configuration file was saved to /usr/share/ovirt-engine/conf/iptables.backup.074609-01032012_1691  * The installation log file is available at: /var/log/engine/engine-setup_2012_01_03_07_44_46.log  * Please use the user "admin" and password specified in order to login into oVirt Engine  * To configure additional users, first configure authentication domains using the 'engine-manage-domains' utility  * To access oVirt Engine please go to the following URL: http://ovirt-manager.demo.local:8080

If you get database creation error, please check the database installation log. If there’s lines saying “Peer authentication failed for user “postgres”" please change authentication method in pg_hba.conf to trust and restart your postgresql-service and run installer again.

Next step is install ovirt-node (Hypervisor). It’s really simple and straightforward. Just get latest iso from http://www.ovirt.org/releases/nightly/binary/ and boot your hypervisor machine with it, install to local disk and do basic configurations: This shouldn’t take long, there is only few things to do. Select disk where you are installing, type root password and go.

Next thing to do is install more hypervisors and connect them to ovirt-engine. I’ll write another post about this with basic configuration examples. Try oVirt today, it’s really competitive alternative for VMware / Citrix and it’s totally open source

Reference :

http://www.linux-kvm.org/page/Management_Tools

http://www.ovirt.org/

http://blog.jaurola.fi/

Beza Antara Fungsi UV Filter, CPL Filter dan ND8 Filter

Banyak jenis sebenarnya filter lens yang ada untuk lens kita.Kalau nak diringkaskan bolehlah kita bagi pada3 jenis filter ni; uv,cpl dan nd8.Filter ni bukan setakat menapis cahaya yang direct datang pada lens,tapi ia juga boleh membantu untuk bagi hasil art pada gambar.Terutamanya kalau nak dapat gambar pemandangan yang cantik.

UV Filter

Ni Filter yang biasanya dapat bila kita beli lens.UV Filter ni simple saja fungsinya.Tapis sinar UV dan protection pada lens.Kalau kita beli lens tu,jangan kedekut nak beli uv filter terus(kalau tak dapat free).Nak elak calar pada lens yang baru beli tu.Harga murah mahal pun tak apa.Ada dua jenis,slim dan biasa.Bezanya nipis tebal saja.

RM25

CPL Filter

Polarizing filter biasanya orang guna untuk bagi gambar efek gelap pada langit.warna langit biru tu timbul terang. Ada juga kalau untuk tangkap gambar produk macam jam tangan biasanya.Bila ambik gambar jam,kurang lah efek pantulan cahaya dari cermin jam tu.jadi boleh nampak detail jarum dalam jam tanpa ada pantulan.

cpl biasanya lebih gelap warnanya dari uv filter

Awan pada langit lagi menyerlah

credit gambar: http://braendan.blogspot.com/2009/01/bw-kasemann-ksm-cpl-filter.html

ND8 Filter

Neutral Density filter (ND filter) adalah jenis filter yang digunakan untuk tangkap gambar air terjun,salji. Ia sebenarnya nak kurangkan amount cahaya yang sampai pada sensor camera.Jadi boleh tambah efek halus pada foto disamping baiki tone.

ND8 berwarna hitam. RM65

Credit gambar:http://www.foxsaver.com/public/picture/66481617

Yangni gabung cpl dan nd8 filter.

Itu lah sikit info pasal jenis filter dan fungsinya.Review jenis biasa-biasa sahaja.Hope dapat bantu korang dapat brief idea sebelum membeli filter.

Tips Shooting Outdoor Photography

Tangkap gambar outdoor ni cantik sebenarnya.Gambar pemandangan mahupun gambar potrait, part warna dia yang best tu.Naik semacam.Tapi part yang susah sikit bila kena bayang-bayang terutamanya time matahari terik.Nanti gambar jadi macam ni

Perasan tak ada bayang-bayang daun,ranting dan pokok pada muka subject.Isy2.Tak cantik macam ni.

Solution Pertama:

Cara yang senang sikit,orang pakai reflector lah.

Yang mana terlindung dengan bayang-bayang pada model tu, boleh lah kita cover dengan reflector.Dia pantul balik cahaya kena dekat model.Nampak natural sikit. Nak tengok beza pakai reflector tak?

Gambar kat atas tu saya ambil dari istock.Cute sungguh!

Orang sekarang suka buat outdoor wedding shoot kan. Memang nak lah pada benda ni.Senang kerja. Reflector ada 5 warna yang ada fungsi-fungsi dia sendiri.Kita explore lah nanti baru nampak bezanya.Kalau nak cari reflector, cari yang boleh lipat dan biarlah ada beg dia sekali.Sebab benda ni kan kalau dah buka,mak aiihh.Pernahlah hari tu customer datang beli reflector ni dengan saya.Kitorang cuba-cuba buka nak test,fuh besar sungguh.

Solution Kedua:

Kalau model/subject menghadap matahari boleh tambah cahaya kan.Tapi nanti dia silau pulak.Terkebil-kebil jadi dia. Kat sini kita kena main dengan kedudukan angle. Try cuba bagi matahari tu 135 degree dari model kita.Sipi-sipi belakang.

Lukisan tak cantik tu biasalah kan.Haha!!

Itu sudut kalau tangkap gambar potret orang.Kalau tangkap gambar pemandangan seperti persekitaran rumah misalnya, disarankan biarlah matahari tu berada belakang kita pulak. Boleh naik contrast warna sekitar rumah tu seperti warna rumput dengan awan.Itulah penangan matahari.

Itu sahaja kali ini.Korang mesti ada buat outdoor jugak kan.Share lah cara korang pulak di bahagian komen ok!