[heading]1.问题描述[/heading]

Ubuntu 16.04 Server LTS升级内核时,每次都跑出来“W: mdadm: /etc/mdadm/mdadm.conf defines no arrays”的提示。明明没有用RAID,查了mdadm.conf也有没有任何相关的配置。虽然不影响使用,但是强迫症患者还是觉得很不爽。

[heading]2.解决办法[/heading]

先删除mdadm.conf文件

[highlight dark=”no”]# rm /etc/mdadm/mdadm.conf[/highlight]

再用update-initramfs命令,自动生成新的mdadm.conf文件。

[highlight dark=”no”]# update-initramfs -u[/highlight]

天下太平。

[heading]1.问题描述[/heading]

对于俺这种升级强迫症患者,Ubuntu的/boot分区接近100%是常见的事。日前发现公司一台测试服务器又提示/boot空间快满。习惯性的想删除内核文件释放空间,运行命令,结果与自己期望相悖,系统报空间不,没法删除旧内核文件。
[highlight dark="no"]# sudo apt-get remove linux-image-4.4.0-28-generic[/highlight]
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
linux-headers-4.4.0-24 linux-headers-4.4.0-24-generic linux-headers-4.4.0-28 linux-headers-4.4.0-28-generic linux-headers-4.4.0-31 linux-headers-4.4.0-31-generic
linux-image-4.4.0-31-generic linux-image-extra-4.4.0-31-generic
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
linux-image-4.4.0-28-generic linux-image-extra-4.4.0-28-generic
0 upgraded, 0 newly installed, 2 to remove and 89 not upgraded.
3 not fully installed or removed.
After this operation, 218 MB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 217969 files and directories currently installed.)
Removing linux-image-extra-4.4.0-28-generic (4.4.0-28.47) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.4.0-28-generic /boot/vmlinuz-4.4.0-28-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.4.0-28-generic /boot/vmlinuz-4.4.0-28-generic
update-initramfs: Generating /boot/initrd.img-4.4.0-28-generic

gzip: stdout: No space left on device
E: mkinitramfs failure cpio 141 gzip 1
update-initramfs: failed for /boot/initrd.img-4.4.0-28-generic with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
dpkg: error processing package linux-image-extra-4.4.0-28-generic (–remove):
subprocess installed post-removal script returned error exit status 1
Removing linux-image-4.4.0-28-generic (4.4.0-28.47) …
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 4.4.0-28-generic /boot/vmlinuz-4.4.0-28-generic
update-initramfs: Deleting /boot/initrd.img-4.4.0-28-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 4.4.0-28-generic /boot/vmlinuz-4.4.0-28-generic
Generating grub configuration file …
Found linux image: /boot/vmlinuz-4.4.0-63-generic
Found initrd image: /boot/initrd.img-4.4.0-63-generic
Found linux image: /boot/vmlinuz-4.4.0-59-generic
Found initrd image: /boot/initrd.img-4.4.0-59-generic
Found linux image: /boot/vmlinuz-4.4.0-38-generic
Found initrd image: /boot/initrd.img-4.4.0-38-generic
Found linux image: /boot/vmlinuz-4.4.0-31-generic
Found initrd image: /boot/initrd.img-4.4.0-31-generic
Found memtest86+ image: /memtest86+.elf
Found memtest86+ image: /memtest86+.bin
done
Errors were encountered while processing:
linux-image-extra-4.4.0-28-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)

[heading]2.解决方法[/heading]

运行以下命令先清除空间,确认/boot分区已有足够空余。
[highlight dark="no"]# sudo apt-get clean
# df -h[/highlight]

再用以下命令确定现在所用内核及已安装内核文件,清除不需要的内核文件。


[highlight dark="no"]# uname -a
# dpkg --get-selections|grep linux-image
# sudo apt-get remove linux-image-4.4.0-28-generic[/highlight]

计划把公司应用后台的数据库服务也统一迁移到docker上,因此起了在docker上部署Oracle数据库的念头。记得以前在docker hub上看到过现成的数据库image,上去一搜,发现不是版本太低就是说被O记要求删除。既然是这样,那O记官方有没以支持呢?放狗一搜,发现O记官方在github上有专门的docker images项目,包含了Java、数据库、应用等等的镜像生成文件。就算是自己生成镜像文件,这些资料也对写Dockerfile很有参考价值。

在github上下载Oracle数据库的docker文件,在OTN下载好Oracle Database 12C的安装包,把zip文件置于OracleDatabase/dockerfiles/12.0.0.2目录下,然后开始Oracle数据库docker的无脑安装 。

1.运行dockerfiles下的buildDockerImage.sh命令

从Oracle Linux的slim-7版本生成数据库镜像文件,该命令支持生成Oracle数据库企业版、标准版和XE版本。俺使用的是企业版。


# ./buildDockerImage.sh -v 12.1.0.2 -e -i

该脚本命令参数说明如下:

-v: version to build
Choose one of: 11.2.0.2 12.1.0.2
-e: creates image based on 'Enterprise Edition'
-s: creates image based on 'Standard Edition 2'
-x: creates image based on 'Express Edition'
-i: ignores the MD5 checksums

开始配置环境,复制安装文件,静默安装数据库,最后生成镜像。大概需要10来分钟时间。

[highlight dark=”no”]注:在生成数据库镜像前,请特别留意Docker的存储驱动配置必须btrfs或overlay2,如果使用aufs在生成过程中会出现各种问题,俺还特意在github上特意开了issue讨论这个问题。[/highlight]

2.在docker容器中运行Oracle数据库


docker run --name \
-p :1521 -p :5500 \
-e ORACLE_SID= \
-e ORACLE_PDB= \
-e ORACLE_CHARACTERSET= \
-v [:]/opt/oracle/oradata \
oracle/database:12.1.0.2-ee

Parameters:
–name: The name of the container (default: auto generated)
-p: The port mapping of the host port to the container port.
Two ports are exposed: 1521 (Oracle Listener), 5500 (OEM Express)
-e ORACLE_SID: The Oracle Database SID that should be used (default: ORCLCDB)
-e ORACLE_PDB: The Oracle Database PDB name that should be used (default: ORCLPDB1)
-e ORACLE_CHARACTERSET:
The character set to use when creating the database (default: AL32UTF8)
-v The data volume to use for the database.
Has to be owned by the Unix user “oracle” or set appropriately.
If omitted the database will not be persisted over container recreation.

[heading]1.问题描述[/heading]

Docker安装后默认的Storage Driver是AUFS,把存储驱动改成overlay2后,系统重启发现Docker daemon无法启动,查看状态提示是docker目录存在多个有效驱动,要求指定存储驱动。[highlight dark=”no”]Error starting daemon: error initializing graphdriver: /data/docker contains several valid graphdrivers: aufs, overlay; Please cleanup or explicitly…[/highlight]

尝试删除Docker目录的aufs目录,结果提示[highlight dark=”no”]rm: cannot remove ‘aufs’: Device or resource busy[/highlight]

[heading]2.原因[/heading]

查找挂载目录,发现 cat /proc/mounts | grep "docker",发现原来是aufs目录被挂载。

[heading]3.解决方法[/heading]
卸载该目录,[highlight dark=”no”] umount /var/lib/docker/aufs[/highlight],问题解决。

懒癌发作,直到春节假期才下定决心把公司的基础架构都迁移到Docker上,随之而来的是一大堆应用重新部署及系统重构的工作。公司大量的应用是基于Oracle数据库构建,所以安装Oracle Database变成了首要任务。虽然安装配置数据库是小菜一碟,但是习惯了登录OTN网站下载安装文件然后照步骤安装,在Linux环境下碰到的第一个问题是在Console的环境下没有浏览器,而下载Oracle 数据库安装文件需要登录OTN网站并同意Oracle的License协议方能下载。

虽然可能利用cookies export这些工具来实现,但是习惯了使用最简单的方法解决问题,直接利用Firefox浏览器可以达到这个目的。在工作计算机上用Firefox登录OTN网站,同意协议后点击下载你所需的数据库安装文件,当下载开始后点击暂停下载,然后在下载任务上右键,选择复制下载链接。

然后登录到Linux终端,用Wget加上复制的链接就可以实现在Linux终端下载OTN文件。