2014.12.20 스터디 내용 정리
SNMP (간이 망 관리 프로토콜)
SNMP는 네트웍 관리 및 네트웍 장치와 그들의 동작을 감시, 통할하는 프로토콜이다.
한마디로 각 시스템별 상태들을 확인 할 수있도록 해주는 것입니다.
솔루션 업체에서 프로젝트 진행시 고객 요구사항에서 필수적으로 요구하는 부분이라고 하네요.
따라서 리눅스 계열이나 윈도우 계열등으로 snmp를 설치해서 해당 시스템 값들을 얻어오면서
모니터링 할 수 있는 사이트까지 만들어 준다고 합니다.
하지만 윈도우계열은 비추천 한다고 하며(설정이 복잡함),
리눅스 계열에서 적용하는 게 편하다고 합니다.
리눅스 계열에서 각 Status를 알아볼 수 있도록 oid (Object ID) 제공해 준다고 합니다.
그리고 oid를 통해서 각 장비에서 원하는 상태값을 얻어내서 모니터링 할 수있다고 합니다
ex) cpu 사용량 , 메모리 상태, hdd 용량 상태등**
CPU times
percentage of user CPU time: .1.3.6.1.4.1.2021.11.9.0
raw user cpu time: .1.3.6.1.4.1.2021.11.50.0
percentages of system CPU time: .1.3.6.1.4.1.2021.11.10.0
raw system cpu time: .1.3.6.1.4.1.2021.11.52.0
percentages of idle CPU time: .1.3.6.1.4.1.2021.11.11.0
raw idle cpu time: .1.3.6.1.4.1.2021.11.53.0
raw nice cpu time: .1.3.6.1.4.1.2021.11.51.0
Memory Statistics
Total Swap Size: .1.3.6.1.4.1.2021.4.3.0
Available Swap Space: .1.3.6.1.4.1.2021.4.4.0
Total RAM in machine: .1.3.6.1.4.1.2021.4.5.0
Total RAM used: .1.3.6.1.4.1.2021.4.6.0
Total RAM Free: .1.3.6.1.4.1.2021.4.11.0
Total RAM Shared: .1.3.6.1.4.1.2021.4.13.0
Total RAM Buffered: .1.3.6.1.4.1.2021.4.14.0
Total Cached Memory: .1.3.6.1.4.1.2021.4.15.0
Disk Statistics
Add the following line to snmpd.conf and restart:
includeAllDisks 10% for all partitions and disks
Disk OID’s
Path where the disk is mounted: .1.3.6.1.4.1.2021.9.1.2.1
Path of the device for the partition: .1.3.6.1.4.1.2021.9.1.3.1
Total size of the disk/partion (kBytes): .1.3.6.1.4.1.2021.9.1.6.1
Available space on the disk: .1.3.6.1.4.1.2021.9.1.7.1
Used space on the disk: .1.3.6.1.4.1.2021.9.1.8.1
Percentage of space used on disk: .1.3.6.1.4.1.2021.9.1.9.1
Percentage of inodes used on disk: .1.3.6.1.4.1.2021.9.1.10.1
.1.3.6.1.4.1.2021.9.1.2.1 <– oid 입니다.**
참고 ( OID 리스트 )http://kaivanov.blogspot.kr/2012/02/linux-snmp-oids-for-cpumemory-and-disk.htmlhttp://www.debianadmin.com/linux-snmp-oids-for-cpumemory-and-disk-statistics.html
(제조사 이름을 달고 나오는 서버 머신등은 oid가 다를 수가 있다고합니다.)**
SNMP 를 구축해서 솔루션으로 사업하는 회사들도 많이 있다고 합니다.
제가 금일 봤던 내용으로는 JAVA runtime, process 를 이용 console로 명령어를
날려서 넘어온 text 값으로 DB에 저장시킨 뒤, 웹에서 각 장비별 상태값들을 그래프 형태로
노출하였다고 합니다.
그리고 일정 횟수 이상 응답이 없거나 하면 알림을 해주는 부분도 구현했다고 하네요.
구글 검색시 여러자료가 많은 걸로 봐서는 꽤나 인기가 있었던 부분들인 듯 합니다.
SNMP 설치 방법**
http://www.liquidweb.com/kb/how-to-install-and-configure-snmp-on-centos/
How To Install and Configure SNMP on CentOS
Category: Technical Support, Tutorials
SNMP 101: The Basics
I. How To Install and Configure SNMP on CentOS**II. How To Change the SNMP Port on CentOS
Introduction
SNMP, or Simple Network Management Protocol, is widely used to communicate with and monitor network devices, servers, and more, all via IP. In this case, we’ll be installing an SNMP agent on a CentOS 6.5 server, which will allow for collection of data from our server, and make the information available to a remote SNMP manager.
Pre-Flight Check
- These instructions are intended for installing SNMP and doing a very basic configuration.
- I’ll be working from a Liquid Web Core Managed CentOS 6.5 server, and I’ll be logged in as root.
Install SNMP and SNMP Utilities
Installing SNMP and some optional SNMP utilities is as simple as running one command:
yum -y install net-snmp net-snmp-utils
Add a Basic Configuration for SNMP
Now, let’s take the default SNMP configuration file, /etc/snmp/snmpd.conf and move it to an alternate location, /etc/snmp/snmpd.conf.orig**.
mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.orig
And now we’ll create a new /etc/snmp/snmpd.conf:
vim /etc/snmp/snmpd.conf
For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor
Insert the following text into the new /etc/snmp/snmpd.conf
# Map 'idv90we3rnov90wer' community to the 'ConfigUser'**# Map '209ijvfwer0df92jd' community to the 'AllUser'# sec.name source communitycom2sec ConfigUser default idv90we3rnov90wercom2sec AllUser default 209ijvfwer0df92jd# Map 'ConfigUser' to 'ConfigGroup' for SNMP Version 2c# Map 'AllUser' to 'AllGroup' for SNMP Version 2c# sec.model sec.namegroup ConfigGroup v2c ConfigUsergroup AllGroup v2c AllUser# Define 'SystemView', which includes everything under .1.3.6.1.2.1.1 (or .1.3.6.1.2.1.25.1)# Define 'AllView', which includes everything under .1# incl/excl subtreeview SystemView included .1.3.6.1.2.1.1view SystemView included .1.3.6.1.2.1.25.1.1view AllView included .1# Give 'ConfigGroup' read access to objects in the view 'SystemView'# Give 'AllGroup' read access to objects in the view 'AllView'# context model level prefix read write notifyaccess ConfigGroup "" any noauth exact SystemView none noneaccess AllGroup "" any noauth exact AllView none none
The above text is noted with basic information on the function of each configuration line. In short, we’re creating two scenarios for polling information from SNMP version 2c.
Note: SNMPv2c contains some security enhancements over SNMPv1 but uses the existing SNMPv1 administration structure, which is “community” based. Areas of improvement include: transport mappings, protocol packet types, and MIB structure elements.
In the first scenario: ConfigUser is assigned to ConfigGroup and may only use SNMP security model2c, ConfigGroup can use the SystemView, SystemView is assigned to two OID sub-trees, and all of this is referenced in an SNMP poll by the secret, and unique community string idv90we3rnov90wer**.
In the second scenario: AllUser is assigned to AllGroup and may only use SNMP security model 2c,AllGroup can use the AllView, AllView is assigned to the entire OID tree, and all of this is referenced in an SNMP poll by the secret, and unique community string 209ijvfwer0df92jd.
Important Tip: Be ABSOLUTELY SURE that you choose a unique community string and replace the community strings in the above examples. Keep each secret, and keep each safe.
Exit vim, and restart the SNMP service to reload the new configuration file:
service snmpd restart
Configure SNMP to start when the server boots:
chkconfig snmpd on
Test the SNMP Configuration
Now let’s test the SNMP configuration… try running the following two commands:
snmpwalk -v 2c -c idv90we3rnov90wer -O e 127.0.0.1snmpwalk -v 2c -c 209ijvfwer0df92jd -O e 127.0.0.1
Note: The default port for SNMP is 161 and 162. If you’re going to connect to SNMP from a remote server, be sure your server’s firewall has the appropriate ports open.
The result for your first command should be about 33 lines, and contain some basic system information. The result for the second command should contain a lot more information about your system, and will likely be thousands of lines.