Which is the agent philosophy?

[davide]

Hello,
I have not well understood which is the philosophy of the agent.

SNMP let monitor every value of an host, why using an agent to do this?

Maybe agent is like an higher level of abstraction (an agent value summarize several SNMP value)?

Why not simply using SNMP?

What can I do with agent that SNMP can't do?

Any clarification for my confusion will be appreciated.

Regards,

Davide.

[Alexei]

A brief SNMP vs ZABBIX agent table:

SNMP agents:

Platforms: Limited
Same config on all platforms: No
High performance: No (in most cases)
Custom parameters: No
Requires root priviledges/SUID binaries: Yes (in most cases)
Can do active checks: No (traps only)

ZABBIX agents:

Platforms: virtually all platforms
Same config on all platforms: Yes
High performance: Yes
Custom parameters: Yes
Requires root priviledges/SUID binaries: No
Can do active checks: Yes

Any questions?

[davide]

Hello Alexei,
thanks for the clear table.

Very important in my opinion are:

- Same config on all platforms THIS IS THE MOST IMPORTANT FEATURE OF THE AGENT. However the agent don't works on all the platforms, for example CISCO router, Environment Monitor, ecc, must have SNMP Acces. Agent are very useful for "computer hosts".
- High Performance (but not al SNMP access have low performance)
- Active check
- No need for root privilege (but also SNMP don't need root privileges)

Davide.

[mcarbonneaux]

SNMP agents:

Platforms: Limited
i'm not ok with that!!! snmp are massively disponible! quasi all network device and appliance! and with net-snmp you have agent on all plateforme where net-snmp compile (that include windows!)...
Same config on all platforms: No
if you use netnmp, it the same conf on all...
High performance: No (in most cases)
(... in most case, but not on all...)
Custom parameters: No
net-snmp are completely customisable (ext. script, embed script perl, dll...)... see on net-snmp doc and cacti sample
Requires root priviledges/SUID binaries: Yes (in most cases)
if you run net-snmp with other port than 161, no need of root priviledge, only needed for metric that can read only from root
Can do active checks: No (traps only)
ok, it's true, but snmp v3 have full auth system and crypto... and use udp, that have less impact on tcp stack on target system

ZABBIX agents:

Platforms: virtually all platforms
not on closed device (firewall,switch...), and the support for many metric are not the same level than linux...
Same config on all platforms: Yes
yes, it's true
High performance: Yes
Custom parameters: Yes
less than net-snmp for the moment...on net-snmtp you can custom with external script, embeded perl, or plugin or with standard mib extension... and with external script the net-snmp deamon cache the request it many request arive in x secondes windows...etc... support multy value in one script... active script tha is run at start on the first request...etc...
Requires root priviledges/SUID binaries: No
(on some system you not be abel to read system metric if your are not root...)
Can do active checks: Yes
yes, it's true

i think the real advance is the simplicity to configure...
the intergration with the server system...
and the active check ok but with auth/crypto...
and active check are not interessting on all situation, because if i need to monitor server that are in dmz... is not very secure to autorize to connect to machine (zabbix server) that are in protected zone...in that way passive are more secure... but need auth and scripto (like snmpv3)...
and need to be more customisable like net-snmp but without complexity of net-snmp...
and support also table, not only simple item...



and udp must be interesting in place of tcp...

[Alexei]

I was talking about general SNMP agent vs ZABBIX agent, not about NET-SNMP.

if you run net-snmp with other port than 161, no need of root priviledge, only needed for metric that can read only from root

Even if a SNMP agent is listening port 1024 or higher, its functionality (interface up/down, for example) requires super-user privileges.

[davide]

From what I understood Zenoss is only SNMP monitoring. Which are the benefits of a totale SNMP based monitoring?

I suppose the enormous availability on SNMP on any platform.

I think that Zabbix can be more simple to configure on supported systems (but firewall/switch/router need SNMP).

[Alexei]

I also didn't mention that ZABBIX agents have very small footprint and we provide support for both ZABBIX server and agents (same vendor support), which is crucial for effective commercial support.

[Alexei]

I think that Zabbix can be more simple to configure on supported systems (but firewall/switch/router need SNMP).

We are going to address SNMP related drawbacks (easy configuration, tables, interface aliases, etc) in the next major release. All this requires careful design to avoid extra complexity, yet it should be reasonably user-friendly.

[mcarbonneaux]

I was talking about general SNMP agent vs ZABBIX agent, not about NET-SNMP.

ok, but net-snmp is the more deployed snmp solution... and generaly can replace the embeded OS snmp solution in many case...

if you compare the deployment of Zabbix agent vs NET-SNMP, is the same effort (a generic config file is suffisant for NET-SNMP and is about 4 lignes of configuration...to define the auth mecanism used and snmp version and comunity version...and the listen interface and tcp port)...

and net-snmp are generaly pre-installed(packaged) on many OS (not only linux/bsdi)...

Even if a SNMP agent is listening port 1024 or higher, its functionality (interface up/down, for example) requires super-user privileges.

is what i sayed, if the metric are only readable by root... not only net-snmp are not abel to read it without root privilege...

and interface up/down status a readable without root on linux (read it on /proc/net/if_inet6 and ioctl SIOCGIFFLAGS)... i'm not sure is the same on all os (SIOCGIFFLAGS are get to linux from solaris...)...

and UDP protocol as less impact on monitored system than tcp (on file handle open for exemple)...

Best regards,
Mathieu

[mcarbonneaux]

We are going to address SNMP related drawbacks (easy configuration, tables, interface aliases, etc) in the next major release.

yes!!! snmp tables support whaoo! it's my dream that zabbix support that!

even if i criticize zabbix vs snmp, i'm rely a fan of zabbix... !

Best regards,
Mathieu

[Markus]

I don't see the case for an argument here. It is perfectly possible for Zabbix to monitor a server through SNMP instead of using the Zabbix agent. It all depends on which option suits your needs best. Choice is good!

Markus

[Frodo]

Monitoring with SNMP can be a pain.
You have to configure the community strings on each server to make it a little bit secure. On Windows-System snmp is not very good implemented. Often you have to install third-party tools.
For me monitoring with a agent is the best way to do.
But on closed systems the only way is snmp. But i really hate the snmptraps.

[mcarbonneaux]

I don't see the case for an argument here. It is perfectly possible for Zabbix to monitor a server through SNMP instead of using the Zabbix agent. It all depends on which option suits your needs best. Choice is good!

Markus

i'm completely ok with that!!!

my say is only about the alexie argument on the choice of the use of zabbix agent vs snmp... not on the quality of zabbix! or zabbix agent !

and i think without snmp support zabbix while be completely usefull for me and for many people...

Monitoring with SNMP can be a pain.
You have to configure the community strings on each server to make it a little bit secure.

is miss understanding of snmp...
snmp v1 have minimum security (community...)
snmp V2 ip filtering
snmp v3 support authentification (radius) et crypto...
and zabbix agent have no support about any security mescanism other than ip/dns filtering...

and for unix system you can repackage netsnmp to automate the configuration ...
and you can use cfengine/scp like solution to deploy configuration (one file like zabbix agent!) on all server...

On Windows-System snmp is not very good implemented. Often you have to install third-party tools.

ok but net-snmp installer exist...

[mcarbonneaux]

i'm reading zabbix agent protocol 1.4x ... http://www.zabbix.com/wiki/doku.php?id=zabbixprotocol
and i've found they are very simple to use tu implemente specialised agent to monitor extremly vaste type metric that zabbix cannot monitor without external script (very low performance!)... without asn/1 snmp complexity (implementing snmp agent in java...is painfull...)....

for sample the jmx zapcat agent!!!! very interesting use of the zabbix protocol!!!