UBUNTU12.04系統特性

 Ubuntu Server 12.04 的新特性一覽表

中文科技資訊:

Ubuntu 12.04 (代號爲 Precise Pangolin) 版本主要側重於發佈、穩定性和質量。Ubuntu 12.04 包含最新的代號爲 Essex 的 OpenStack 版本，以及一項名爲 MAAS 的新特性。此外，可使用 Juju 輕鬆的部署集中式的 CharmStore 。還包含一項名爲 AWSOME 的新技術。

這些技術將 Ubuntu Server 定位爲最佳的可伸縮計算的服務器操作系統，同時在持續集成、發佈和測試的質量上得到了最大的重視。

OpenStack
OpenStack 項目更新到最新你名爲 Essex 的版本，對 nova 用戶默認使用 /bin/false。
新的二進制包，nova-cert 需要進行解密圖片，移除對 M2Crypto 的依賴。
Quantum 分成 quantum 和 quantum 客戶端包
Glance 包含新的配置文件結構
nova 默認使用 nova-rootwrap ，提供更好的、更細粒度的安全層
從 horizon 中移除 openstackx
移除 ajaxconsole 改用基於 VNC 的解決方案
移除 ec2 admin api.
Quantum, Melange, 和 Nova 網絡模塊進行合併
添加許多 OSAPI 擴展
euca-upload-bundle 可與 keystone 一起工作
OpenStack 組件可通過 Juju Charms 進行發佈
Keystone 更新到 Keystone-light (redux 分支). Keystone-light 是一個新的重寫的版本，替換原來在 11.10 中的版本。
Glance 在升級後需要進行手工的數據庫移植
默認必須在受保護的網絡中安裝 Openstack，因爲多數組件使用 http （非安全）進行傳輸。

MAAS
MAAS (Metal as a Service)爲物理服務器帶來了雲環境語言，可以輕鬆的在已有硬件基礎上發佈任何服務，並可根據需要進行伸縮以及動態下線。

AWSOME
AWSOME (“Any Web Service over Me”) 爲 OpenStack 提供了 IAAS API’s ，可輕鬆發佈和管理基於 AWS 和 OpenStack 的雲服務。

Juju
Juju CharmStore 現可無需本地 charms 環境直接發佈 charmed 服務。
允許使用不同的服務單位添加下屬服務，將部署到相同的容器中，並互相識別。
增加機器約束，方便用戶選擇他們發佈服務所需的硬件配置。

Java
可通過 Universe 軟件庫獲取 Apache Tomcat 7.0.26 ，當然繼續支持 Tomcat 6.0.35
請注意 Tomcat 7 將在 Ubuntu 12.10 中替換 Tomcat 6.
軟庫庫中同時提供 Apache ActiveMQ 5.5.0 、Jenkins 1.424.6 LTS、OpenJDK 7 (緊密貼合 Oracle Java 7)、Groovy 1.8.6、Scala 2.9.1 和 Clojure 1.1.0
請注意 OpenJDK 7 將是 Ubuntu 12.10 中默認的 Java 實現。

虛擬化
包含 Xen 並且官方支持
爲 Ubuntu 作爲 Zen 虛擬化服務提供工具 (dom0)
Libvirt integration/Xen domains manageable through libvirt or any frontend that uses libvirt.
Guest installations in HVM mode will use optimized paravirt drivers out of the box.
LXC 提升包括：
The ability for stock 12.04 images to boot in a container
Apparmor protection to increase security
Support for lvm- and btrfs-backed containers
New ubuntu-cloud template for simple creation of containers based on published Ubuntu Cloud images.
KVM (version 1.0) 和 Libvirt 提升包括：
QED (Qemu enhanced disk format) support
AHCI protocol support
Nested guest support forIntel processors (in addition to AMD support)
Public API to invoke suspend/resume on the host from libvirt
STP and VLAN filtering from libvirt
Bandwidth QoS control in libvirt
CPU 帶寬限制支持

文件系統
CEPH 客戶端庫, librbd 和 librados 添加到 KVM 的支持中
CIFS 使用文件系統緩存以提升性能
軟 RAID 支持壞塊管理

ARM 支持
提供 OpenMPI 1.5 for ARM  (889644)
openmpi 1.5 改進對 ARM 的支持，不過目前還是 beta 版本。

其他
Query2, 一個新的元數據服務，用來描述 Ubuntu 雲圖片以及其可用性，提供一個 JSON 格式的文件用來描述 cloud-images.ubuntu.com 上的圖片存儲和官方 Ubuntu 圖片的狀態
新的 Zentyal 包
These packages are a rename of the existing ebox packages along with a new upstream release fixing known issues in the current ebox packages in Ubuntu 11.10.
Resara, 一個開源的 Linux 域控制器和文件服務器，基於 Samba4.
acpid introduced to both Server and Cloud images by default.
Chef 0.8.16 (948437) and corresponding Ohai packages (948438) removed from precise at the request of OpsCode.
應 Eucalyptus 的要求移除 Eucalyptus 2.0.1 (953405)

通用架構
Up until Ubuntu 11.10, administrator access using the sudo tool was granted via the “admin” Unix group. In Ubuntu 12.04, administrator access will be granted via the “sudo” group. This makes Ubuntu more consistent with the upstream implementation and Debian. For compatibility purposes, the “admin” group will continue to provide sudo/administrator access in 12.04.
默認禁用休眠功能(suspend to disk) ，因爲發現這功能不可靠，而且兩種不同的掛起模式讓人混淆，詳情請看 bug 812394.
pm-utils now has two new scripts to power down USB and various PCI devices in battery mode. A number of desktop packages were fixed to wake up less often. Both of these reduce power consumption and thus improve battery lifetime.
resolvconf is now used to manage /etc/resolv.conf on all Ubuntu systems. You can learn more here
Backports are now more easily accessible -- to enable users to more easily receive new versions of software, the Ubuntu Backports repository is now enabled by default. Packages from backports will not be installed by default — they must explicitly be selected in package management software. However, once installed, packages from backports will automatically be upgraded to newer versions.
DVD Images -- the DVD images have been cleaned up significantly reducing their size to around 1.5GB to ease consumption. The remaining software remains available via download.

Linux v3.2.14 內核
Ubuntu 12.04 LTS ships with an updated kernel moving from the mainline v3.0 series to the mainline v3.2 series. At release we are shipping with the Ubuntu 3.2.0-23.36 kernel which is based on the v3.2.14 upstream stable Linux kernel. The mainline v3.0 to v3.2 stable series update brings a number of new features. Some highlights include:
ext4 gains support for larger base block sizes
btrfs has more work addressing data integrity issues
device mapper gains thin provisioning and recursive snapshots
more work to improve performance under high writeback load
networking improvements for congested networks
ext3 moves to using filesystem barriers
memory allocator improvements
VFS scalability improvements
a new iSCSI implementation
software wait gains bad block management
Key changes in the Ubuntu kernel since the 3.0.0-12.20 Ubuntu kernel as shipped in the 11.10 Ubuntu release include:
Rebase to upstream stable Linux kernel v3.2.14.
The amd64 -generic and -server kernel flavors have been merged into a single -generic kernel flavor for Ubuntu 12.04. Given the few differences that existed between the two flavors, it only made sense to merge the two and reduce the overall maintenance burden over the life of this LTS release.
Support for a new armhf kernel flavor has been introduced.
The non-smp PowerPC kernel flavor has been removed. All hardware currently supported by the non-smp PowerPC kernel flavor should also be supported by the smp PowerPC kernel flavor.
RC6 is enabled by default for Sandy Bridge systems. RC6 is a technology which allows the GPU to go into a very low power consumption state when the GPU is idle (down to 0W). It results in considerable power savings when this stage is activated. When comparing under idle loads with machine state where RC6 is disabled, improved power usage of around 40-60% has been witnessed.
An improved set of jack detection patches has been backported from the upstream v3.3 Linux kernel.
An updated AppArmor patch set has been included to better align with what is landing upstream.
Applied and enabled the seccomp filters feature which uses the packet filtering machinery (BPF) to restrict access to system calls.
A set of kexec fixes for arm from v3.3-rc1 has also been backported.
We’ve also conducted an extensive review of Ubuntu kernel configs and made numerous config changes as a result.

Upstart 1.5
Upstart 更新到 1.5. Upstart Technical Overview 提供更詳細的細節

GNU Toolchain
Ubuntu 12.04 包含默認的工具鏈：GCC 4.6.3 (and changes from Linaro GCC 4.6-2012.02), binutils 2.22, eglibc 2.15, and Linaro gdb 7.4-2012.04.
與 11.10 版本比較主要是一些增量的改動和 bug 修復
更新的前端以更好的支持標準 (Ada 2012, Objective-C 2.0, improved experimental support for the upcoming C++0x ISO C++ standard, Fortran 2003 and 2008 improvements, new Go frontend)
改進優化、更好的過程優化和鏈接時間優化。
更多的信息請看 (GCC-4.6, GCC-4.5, binutils, gas, ld, gdb).

Python Toolchain
Ubuntu 12.04 包含 Python 2.7.3 和 Python 3.2.3，不再提供 Python 2.6
該版本爲 Python 3 提供擴展支持, 包括 Python 3 移植版本的：python-dbus, python-feedparser, germinate, lazr.ui, wadllib, python-defer, python-keyring, and python-qt4 now included, among others.

Java Toolchain
默認的 Java 運行環境採用 OpenJDK 6b24 (IcedTea 1.11.1). 同時也提供 OpenJDK 7u3 (IcedTea 2.1)