今天在一台新的CentOS6服务器上配置PHP环境，用yum的方式安装，碰到问题了：
Error: xz compression not available
问题是这样来的，我参照我之前的博文安装步骤执行：《CentOS7下yum安装PHP5.6》，直到出现错误，才想起原来我当前的系统是CentOS6的！都是粗心惹的祸:-(
网上找到了解决的方法，即移除新版的epel–release：
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yum remove epel–release
rm –rf /var/cache/yum/x86_64/6/epel/
yum clean all
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最好执行clean，有一次就是没执行，留有了缓存，被摆了一道。然后重新再安装6.x版本的epel–release
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yum install epel–release
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寫這篇最主要推廣讓網站都支援 HTTPS 加密連線及 HTTP2 協定，對於網站為什麼要支援 HTTP2，可以直接參考 ihower 寫的說明文章，最近在玩 Facebook, Line, Telegram Bot 時，填寫 Webhook URL，都強制要填寫 https:// 開頭，所以更不能忽略 HTTPS 了。，去年底寫了一篇 Let’s Encrypt 開放申請免費 SSL 憑證 推廣 Let’s Encrypt 的貢獻，讓買不起憑證，又想玩看看 HTTP2 的開發者可以用很簡單的方式來安裝及自動更新憑證，而 gslin 大為了推廣 HTTPS 也做了一個網站教學，文章寫得相當清楚，支援 Apache 及 Nginx 設定。
如果主機是使用 Amazone EC2，可以直接用 AWS Certificate Manager，用 AWS 的好處就是只要透過後台介面搭配 ELB 就可以直接設定好 HTTPS 對應到 EC2 主機，壞處就是直接被綁死，將來如果不要使用 AWS，要轉移機器會相當痛苦。所以本篇會紀錄如何用 Nginx 搭配 Let’s Encrypt。為了方便部署機器，我們選用 dehydrated 來設定 Let’s Encrypt，好處就是不用安裝 Python 套件，官方網站提供的安裝方式需要安裝 Python 相關環境。透過 wget 將 dehydrated 安裝到 /etc/dehydrated/ 底下
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$ mkdir -p /etc/dehydrated/$ wget https://raw.githubusercontent.com/lukas2511/dehydrated/master/dehydrated -O /etc/dehydrated/dehydrated$ chmod 755 /etc/dehydrated/dehydrated |
建立 dehydrated config 設定檔
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$ echo "WELLKNOWN=/var/www/dehydrated" > /etc/dehydrated/config $ mkdir -p /var/www/dehydrated |
Nginx 設定，先在 80 port 的 Server section 內寫入底下設定:
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location /.well-known/acme-challenge/ { alias /var/www/dehydrated/;} |
可以先丟個檔案到 /var/www/dehydrated/ 確定網站可以正常讀取檔案，接著透過 dehydrated 指令產生 SSL 設定檔
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$ /etc/dehydrated/dehydrated -c -d fbbot.wu-boy.com |
執行上述指令會看到底下結果
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# INFO: Using main config file /etc/dehydrated/configProcessing fbbot.wu-boy.com + Signing domains... + Generating private key... + Generating signing request... + Requesting challenge for fbbot.wu-boy.com... + Responding to challenge for fbbot.wu-boy.com... + Challenge is valid! + Requesting certificate... + Checking certificate... + Done! + Creating fullchain.pem... + Done! |
最後在設定一次 nginx
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server { # don't forget to tell on which port this server listens listen 80; # listen on the www host server_name fbbot.wu-boy.com; # and redirect to the non-www host (declared below) return 301 https://fbbot.wu-boy.com$request_uri;}server { listen 0.0.0.0:443 ssl http2; server_name fbbot.wu-boy.com; location /.well-known/acme-challenge/ { alias /var/www/dehydrated/; } ssl_certificate /etc/dehydrated/certs/fbbot.wu-boy.com//fullchain.pem; ssl_certificate_key /etc/dehydrated/certs/fbbot.wu-boy.com/privkey.pem; location / { proxy_pass http://localhost:8081; }} |
上面是將 80 port 自動轉到 https，如果下次要重新 renew 的時候才不會又要打開 80 port 一次。
每天半夜可以自動 renew 一次，請參考 https://letsencrypt.tw/ 最後章節
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0 0 * * * root sleep $(expr $(printf "\%d" "0x$(hostname | md5sum | cut -c 1-8)") \% 86400); ( /etc/dehydrated/dehydrated -c -d fbbot.wu-boy.com; /usr/sbin/service nginx reload ) > /tmp/dehydrated-fbbot.wu-boy.com.log 2>&1 |
除了這方法之外，也可以使用 Certbot 來自動更新憑證，但是這方式就是要安裝 Python 環境，不過也不是很難就是了，可以直接參考這篇『NGINX 使用 Let’s Encrypt 免費 SSL 憑證設定 HTTPS 安全加密網頁教學』。結論就是你可以在網路上找到超多種方法來申請 Let’s Encrypt 憑證，就找到自己覺得不錯的方法即可，而我是認為不用安裝 Python 環境的方式最適合部署了。
refer by https://blog.wu-boy.com/2016/10/website-support-http2-using-letsencrypt/
http://www.cnblogs.com/me115/p/5698787.html
在 php 中有設定最大上傳檔案大小 如果想上傳較大的 *.sql 檔案 phpMyAdmin 會有錯誤跳出，不允許上傳檔案 在這種情況以 phpMyAdmin 內建的功能我們有兩種解決方案： (
Source: [程式泥沼中打滾] – phpMyAdmin 大型 MySQL 檔案匯入解決方案 @ 豚丸の硬いブログ :: 痞客邦 PIXNET ::
Type sudo update-alternatives --config editor
You will get a text like below.
There are 4 choices for the alternative editor (providing /usr/bin/editor).
Selection Path Priority Status
------------------------------------------------------------
* 0 /bin/nano 40 auto mode
1 /bin/ed -100 manual mode
2 /bin/nano 40 manual mode
3 /usr/bin/vim.basic 30 manual mode
4 /usr/bin/vim.tiny 10 manual mode
Press enter to keep the current choice[*], or type selection number: 3
Find vim.basic or vim.tiny selection number. Type it and press enter. Next time when you open visudo your editor will be vim
前言（扯犊子）：做为一名在前线的信息安全从业人员，应急响应技术是必不可缺的，在常见的安全保障模型P2DR模型中，response（响应）占据了其中重要的一个环节。
Source: Linux 应急响应总结
http://cyrilwang.blogspot.tw/2012/11/iptables-ssh.html
http://blog.pnyet.web.id/2013/01/07/solved-error-spine-timed-out-while-processing-hosts-internal.html
Few days ago I’ve a problem when installing cacti 0.8.8a, and only 3 devices that successfully graphed. My cacti running on CentOS 6.3 x86_64 with core i7 and 8GB ram, 240GB SSD and will used for populate about 3000 – 3500 data sources. First time I ran the cacti and everything work fine and I can add about 4 graphs on two devices and the graph is normal.
The problem come after generate about 300 graphs and the new graph doesn’t show. I got the following error message from cacti.log:
01/02/2013 06:59:06 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 06:59:06 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:00:08 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:00:08 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:01:07 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:01:07 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:02:08 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:02:08 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:03:10 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:03:10 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal 01/02/2013 07:04:07 AM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal
After got the error log in above, I did the following steps:
1. Modify PHP execution time limit ini php.ini and change the maximum execution time from 60 second to 180 second
# vi php.ini
max_execution_time = 180
2. Increase script server time out value from 60 second to 180 or above depend on yours, go to cacti console enter to setting menu and then change “Script and Script Server Timeout Value” from 60 to 180 or above.
If two step in above doesn’t work
also try to modify mysql & php config.
How to change max_connections
You can change max_connections while MySQL is running via SET:
mysql> SET GLOBAL max_connections = 5000;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE "max_connections";
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 5000 |
+-----------------+-------+
1 row in set (0.00 sec)
wget -O speedtest https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py
chmod +x speedtest
./speedtest
In this how-to we are going to show you how to install and setup complete network monitoring application called Cacti using Net-SNMP tool on RHEL/CentOS/Fedora.