juju bootstrap fails with error from mongodb

[Raghavendra]

i installed juju from snap
ubuntu version-> 18.04.02

groupadd --system lxd
snap install juju --classic

juju version => 2.5.1

but when executed juju bootstrap. i got below error

juju bootstrap --bootstrap-series=trusty localhost devlocal

Error:-
        ERROR juju.mongo mongo.go:567 could not set the value of "/proc/sys/net/core/somaxconn" to "16384" because of: "/proc/sys/net/core/somaxconn" does not exist, will not set "16384"
     ERROR juju.mongo mongo.go:567 could not set the value of "/proc/sys/net/core/netdev_max_backlog" to "1000" because of: "/proc/sys/net/core/netdev_max_backlog" does not exist, will not set "1000"
     ERROR juju.mongo mongo.go:567 could not set the value of "/sys/kernel/mm/transparent_hugepage/enabled" to "never" because of: open /sys/kernel/mm/transparent_hugepage/enabled: permission denied
     ERROR juju.mongo mongo.go:567 could not set the value of "/sys/kernel/mm/transparent_hugepage/defrag" to "never" because of: open /sys/kernel/mm/transparent_hugepage/defrag: permission denied
     INFO juju.mongo mongo.go:439 Ensuring mongo server is running; data directory /var/lib/juju; port 37017
     INFO juju.mongo mongo.go:640 installing [juju-mongodb]
     INFO juju.packaging.manager utils.go:64 Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install juju-mongodb
    7 INFO juju.service service.go:214 Installing and starting service &{Service:{Name:juju-db Conf:{Desc:juju state database Transient:false AfterStopped: Env:map[] Limit:map[fsize:unlimited cpu:unlimited as:unlimited memlock:unlimited nofile:64000 nproc:64000] Timeout:300 ExecStart:/usr/lib/juju/bin/mongod --dbpath '/var/lib/juju/db' --sslPEMKeyFile '/var/lib/juju/server.pem' --sslPEMKeyPassword=ignored --port 37017 --syslog --journal --replSet juju --quiet --oplogSize 1024 --ipv6 --auth --keyFile '/var/lib/juju/shared-secret' --sslOnNormalPorts --noprealloc --smallfiles ExecStopPost: Logfile: ExtraScript: ServiceBinary: ServiceArgs:[]}}}
     ERROR juju.service service.go:224 retrying start request (exec ["start" "--system" "juju-db"]: exit status 1 (start: Job failed to start))
     ERROR juju.service service.go:224 retrying start request (exec ["start" "--system" "juju-db"]: exit status 1 (start: Job failed to start))
     ERROR juju.service service.go:224 retrying start request (exec ["start" "--system" "juju-db"]: exit status 1 (start: Job failed to start))
     ERROR failed to start mongo: exec ["start" "--system" "juju-db"]: exit status 1 (start: Job failed to start)
    ERROR failed to bootstrap model: subprocess encountered error code 1