rs01:SECONDARY> db.adminCommand({buildInfo: true})
{
        "version" : "2.6.11",
        "gitVersion" : "d00c1735675c457f75a12d530bee85421f0c5548",
        "OpenSSLVersion" : "",
        "sysInfo" : "Linux build4.ny.cbi.10gen.cc 2.6.32-431.3.1.el6.x86_64 #1 SMP Fri Jan 3 21:39:27 UTC 2014 x86_64 BOOST_LIB_VERSION=1_49",
        "loaderFlags" : "-fPIC -pthread -Wl,-z,now -rdynamic",
        "compilerFlags" : "-Wnon-virtual-dtor -Woverloaded-virtual -fPIC -fno-strict-aliasing -ggdb -pthread -Wall -Wsign-compare -Wno-unknown-pragmas -Winvalid-pch -pipe -Werror -O3 -Wno-unused-function -Wno-deprecated-declarations -fno-builtin-memcmp",
        "allocator" : "tcmalloc",
        "versionArray" : [
                2,
                6,
                11,
                0
        ],
        "javascriptEngine" : "V8",
        "bits" : 64,
        "debug" : false,
        "maxBsonObjectSize" : 16777216,
        "ok" : 1
}

rs01:SECONDARY> db.adminCommand({hostInfo: true})
{
        "system" : {
                "currentTime" : ISODate("2016-07-25T08:23:47.877Z"),
                "hostname" : "host1",
                "cpuAddrSize" : 64,
                "memSizeMB" : 122953,
                "numCores" : 16,
                "cpuArch" : "x86_64",
                "numaEnabled" : false
        },
        "os" : {
                "type" : "Linux",
                "name" : "Ubuntu",
                "version" : "14.04"
        },
        "extra" : {
                "versionString" : "Linux version 3.13.0-66-generic (buildd@lgw01-26) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #108-Ubuntu SMP Wed Oct 7 15:20:27 UTC 2015",
                "libcVersion" : "2.19",
                "versionSignature" : "Ubuntu 3.13.0-66.108-generic 3.13.11-ckt27",
                "kernelVersion" : "3.13.0-66-generic",
                "cpuFrequencyMHz" : "2494.048",
                "cpuFeatures" : "fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm xsaveopt fsgsbase smep erms",
                "pageSize" : NumberLong(4096),
                "numPages" : 31476120,
                "maxOpenFiles" : 999999
        },
        "ok" : 1
}